diff --git a/app/lib/cds_synchronizer.rb b/app/lib/cds_synchronizer.rb
index f32108d8a..c2adbd106 100644
--- a/app/lib/cds_synchronizer.rb
+++ b/app/lib/cds_synchronizer.rb
@@ -29,6 +29,8 @@ def download
     end
 
     def apply
+      raise WrongEnvironmentError unless TradeTariffBackend.uk?
+
       check_tariff_updates_failures
       check_sequence
 
@@ -64,6 +66,8 @@ def apply
     end
 
     def rollback(rollback_date, keep: false)
+      raise WrongEnvironmentError unless TradeTariffBackend.uk?
+
       Rails.autoloaders.main.eager_load
 
       TradeTariffBackend.with_redis_lock do
@@ -71,7 +75,6 @@ def rollback(rollback_date, keep: false)
 
         updates = TariffSynchronizer::CdsUpdate.where { issue_date > date }
         update_filenames = updates.pluck(:filename)
-
         Sequel::Model.db.transaction do
           # Delete actual data
           oplog_based_models.each do |model|
diff --git a/app/lib/taric_importer.rb b/app/lib/taric_importer.rb
index dfe5935de..2f2cde282 100644
--- a/app/lib/taric_importer.rb
+++ b/app/lib/taric_importer.rb
@@ -22,13 +22,12 @@ def initialize(taric_update)
   end
 
   def import
-    filename = determine_filename(@taric_update.file_path)
-    return unless proceed_with_import?(filename)
-
     handler = XmlProcessor.new(@taric_update.issue_date)
+
     file = TariffSynchronizer::FileService.file_as_stringio(@taric_update)
     XmlParser::Reader.new(file, 'record', handler).parse
-    post_import(file_path: @taric_update.file_path, filename:)
+
+    Rails.logger.info "Successfully imported Taric file: #{@taric_update.filename}"
   end
 
   class XmlProcessor
@@ -54,41 +53,4 @@ def taric_failed_log(exception, hash)
       end
     end
   end
-
-  private
-
-  def proceed_with_import?(filename)
-    return true unless TradeTariffBackend.use_cds?
-
-    TariffSynchronizer::TaricUpdate.find(filename: filename[0, 30]).blank?
-  end
-
-  def post_import(file_path:, filename:)
-    create_update_entry(file_path:, filename:) if TradeTariffBackend.use_cds?
-    Rails.logger.info "Successfully imported Taric file: #{@taric_update.filename}"
-  end
-
-  def create_update_entry(file_path:, filename:)
-    file_size = determine_file_size(file_path)
-    issue_date = Date.parse(filename.scan(/[0-9]{8}/).last)
-    TariffSynchronizer::TaricUpdate.find_or_create(
-      filename: filename[0, 30],
-      issue_date:,
-      filesize: file_size,
-      state: 'A',
-      applied_at: Time.zone.now,
-      updated_at: Time.zone.now,
-    )
-  end
-
-  def determine_file_size(file_path)
-    file_size = File.size(file_path)
-    return file_size if file_size <= 214_748_364_7
-
-    file_size / 1024
-  end
-
-  def determine_filename(file_path)
-    File.basename(file_path)
-  end
 end
diff --git a/app/lib/taric_synchronizer.rb b/app/lib/taric_synchronizer.rb
index 85ea9018a..0ed343548 100644
--- a/app/lib/taric_synchronizer.rb
+++ b/app/lib/taric_synchronizer.rb
@@ -47,6 +47,8 @@ def download
     end
 
     def apply
+      raise WrongEnvironmentError unless TradeTariffBackend.xi?
+
       check_tariff_updates_failures
       check_sequence
 
@@ -78,6 +80,8 @@ def apply
     #
     # NOTE: this does not remove records from initial seed
     def rollback(rollback_date, keep: false)
+      raise WrongEnvironmentError unless TradeTariffBackend.xi?
+
       TradeTariffBackend.with_redis_lock do
         date = Date.parse(rollback_date.to_s)
 
@@ -122,7 +126,7 @@ def rollback(rollback_date, keep: false)
           end
         end
 
-        Rails.logger.info "Rolled back to #{date}. Forced keeping records: #{!!keep}"
+        Rails.logger.info "Rolled back to #{date}. Forced keeping records: #{!keep.nil?}"
       end
     rescue Redlock::LockError
       Rails.logger.warn("Failed to acquire Redis lock for rollback to #{rollback_date}. Keep records: #{keep}")
diff --git a/app/lib/tariff_synchronizer.rb b/app/lib/tariff_synchronizer.rb
index 65ea9e717..d8b0fd955 100644
--- a/app/lib/tariff_synchronizer.rb
+++ b/app/lib/tariff_synchronizer.rb
@@ -1,5 +1,6 @@
 module TariffSynchronizer
   class FailedUpdatesError < StandardError; end
+  class WrongEnvironmentError < StandardError; end
 
   delegate :instrument, :subscribe, to: ActiveSupport::Notifications
 
diff --git a/app/lib/trade_tariff_backend.rb b/app/lib/trade_tariff_backend.rb
index 7f17fd51e..a12d94ccb 100644
--- a/app/lib/trade_tariff_backend.rb
+++ b/app/lib/trade_tariff_backend.rb
@@ -39,10 +39,6 @@ def admin_email
       ENV.fetch('TARIFF_SYNC_EMAIL')
     end
 
-    def use_cds?
-      ENV['CDS'] == 'true'
-    end
-
     def patch_broken_taric_downloads?
       ENV['PATCH_BROKEN_TARIC_DOWNLOADS'] == 'true'
     end
@@ -168,7 +164,7 @@ def check_query_count?
     end
 
     def excess_query_threshold
-      @excess_query_threshold ||= ENV['EXCESS_QUERY_THRESHOLD'].presence&.to_i || 0
+      @excess_query_threshold ||= ENV['EXCESS_QUERY_THRESHOLD'].presence.to_i
     end
 
     def api_version(request)
diff --git a/app/workers/apply_worker.rb b/app/workers/apply_worker.rb
index 1273a0c2e..bb5fdddb9 100644
--- a/app/workers/apply_worker.rb
+++ b/app/workers/apply_worker.rb
@@ -4,7 +4,7 @@ class ApplyWorker
   sidekiq_options queue: :rollbacks, retry: false
 
   def perform
-    if TradeTariffBackend.use_cds?
+    if TradeTariffBackend.uk?
       CdsSynchronizer.apply
     else
       TaricSynchronizer.apply
diff --git a/app/workers/download_worker.rb b/app/workers/download_worker.rb
index a3e195813..f64fa11ac 100644
--- a/app/workers/download_worker.rb
+++ b/app/workers/download_worker.rb
@@ -4,7 +4,7 @@ class DownloadWorker
   sidekiq_options queue: :rollbacks, retry: false
 
   def perform
-    if TradeTariffBackend.use_cds?
+    if TradeTariffBackend.uk?
       CdsSynchronizer.download
     else
       TaricSynchronizer.download
diff --git a/app/workers/rollback_worker.rb b/app/workers/rollback_worker.rb
index 1381efdba..2a6795946 100644
--- a/app/workers/rollback_worker.rb
+++ b/app/workers/rollback_worker.rb
@@ -4,7 +4,7 @@ class RollbackWorker
   sidekiq_options queue: :rollbacks, retry: false
 
   def perform(date, redownload = false)
-    if TradeTariffBackend.use_cds?
+    if TradeTariffBackend.uk?
       CdsSynchronizer.rollback(date, keep: redownload)
     else
       TaricSynchronizer.rollback(date, keep: redownload)
diff --git a/lib/tasks/tariff.rake b/lib/tasks/tariff.rake
index 5b80bfcd6..429fc04c1 100644
--- a/lib/tasks/tariff.rake
+++ b/lib/tasks/tariff.rake
@@ -33,7 +33,7 @@ namespace :tariff do
   namespace :sync do
     desc 'Update database by downloading and then applying TARIC or CDS updates via worker'
     task download_apply_and_reindex: %i[environment class_eager_load] do
-      if TradeTariffBackend.use_cds?
+      if TradeTariffBackend.uk?
         CdsUpdatesSynchronizerWorker.perform_async(true, true)
       else
         TaricUpdatesSynchronizerWorker.perform_async(true)
@@ -42,7 +42,7 @@ namespace :tariff do
 
     desc 'Download pending Taric or CDS update files, Update tariff_updates table'
     task download: %i[environment class_eager_load] do
-      if TradeTariffBackend.use_cds?
+      if TradeTariffBackend.uk?
         CdsSynchronizer.download
       else
         TaricSynchronizer.download
@@ -51,7 +51,7 @@ namespace :tariff do
 
     desc 'Apply pending updates for Taric or CDS'
     task apply: %i[environment class_eager_load] do
-      if TradeTariffBackend.use_cds?
+      if TradeTariffBackend.uk?
         CdsSynchronizer.apply
       else
         TaricSynchronizer.apply
@@ -61,7 +61,7 @@ namespace :tariff do
     desc 'Rollback to specific date in the past'
     task rollback: %w[environment class_eager_load] do
       if ENV['DATE']
-        if TradeTariffBackend.use_cds?
+        if TradeTariffBackend.uk?
           CdsSynchronizer.rollback(ENV['DATE'], keep: ENV['KEEP'])
         else
           TaricSynchronizer.rollback(ENV['DATE'], keep: ENV['KEEP'])
diff --git a/spec/integration/taric_synchronizer_spec.rb b/spec/integration/taric_synchronizer_spec.rb
index e1d9f4e0e..8dc3e88db 100644
--- a/spec/integration/taric_synchronizer_spec.rb
+++ b/spec/integration/taric_synchronizer_spec.rb
@@ -46,8 +46,6 @@
           allow(instance).to receive(
             :persist,
           ).and_raise OpenSearch::Transport::Transport::SnifferTimeoutError
-
-          allow(TariffSynchronizer::TaricUpdate).to receive(:find).and_return(nil)
         end
 
         it 'stops syncing' do
@@ -67,8 +65,6 @@
           allow(instance).to receive(
             :persist,
           ).and_raise Timeout::Error
-
-          allow(TariffSynchronizer::TaricUpdate).to receive(:find).and_return(nil)
         end
 
         it 'stops syncing' do
@@ -175,13 +171,13 @@
     end
 
     describe '#apply', truncation: true do
-      xit 'raises a wrong environment error' do
+      it 'raises a wrong environment error' do
         expect { described_class.apply }.to raise_error TariffSynchronizer::WrongEnvironmentError
       end
     end
 
     describe '#rollback', truncation: true do
-      xit 'raises a wrong environment error' do
+      it 'raises a wrong environment error' do
         expect { described_class.rollback(Time.zone.yesterday, keep: true) }.to raise_error TariffSynchronizer::WrongEnvironmentError
       end
     end
diff --git a/spec/unit/cds_synchronizer_spec.rb b/spec/unit/cds_synchronizer_spec.rb
index 0547fa7ac..ad766e609 100644
--- a/spec/unit/cds_synchronizer_spec.rb
+++ b/spec/unit/cds_synchronizer_spec.rb
@@ -109,7 +109,7 @@
     end
 
     context 'with xi service' do
-      xit 'raises a wrong environment error' do
+      it 'raises a wrong environment error' do
         allow(TradeTariffBackend).to receive(:service).and_return('xi')
         expect { described_class.apply }.to raise_error TariffSynchronizer::WrongEnvironmentError
       end
@@ -126,7 +126,7 @@
     end
 
     context 'with xi service' do
-      xit 'raises a wrong environment error' do
+      it 'raises a wrong environment error' do
         allow(TradeTariffBackend).to receive(:service).and_return('xi')
         expect { described_class.rollback(Time.zone.yesterday, keep: true) }.to raise_error TariffSynchronizer::WrongEnvironmentError
       end
diff --git a/spec/unit/taric_synchronizer_spec.rb b/spec/unit/taric_synchronizer_spec.rb
index dafa19aa3..f5795494e 100644
--- a/spec/unit/taric_synchronizer_spec.rb
+++ b/spec/unit/taric_synchronizer_spec.rb
@@ -101,6 +101,7 @@
         allow_any_instance_of(TaricImporter).to receive(:import)
         allow(TariffSynchronizer::TariffLogger).to receive(:failed_update)
         allow(TradeTariffBackend).to receive(:service).and_return('xi')
+        allow(TradeTariffBackend).to receive(:service).and_return('xi')
         applied_update
         pending_update
       end
@@ -148,6 +149,7 @@
       before do
         failed_update
         allow(TradeTariffBackend).to receive(:service).and_return('xi')
+        allow(TradeTariffBackend).to receive(:service).and_return('xi')
       end
 
       it 'does not apply pending updates' do
@@ -171,7 +173,7 @@
     end
 
     context 'with uk service' do
-      xit 'will raise an wrong environment error' do
+      it 'will raise an wrong environment error' do
         allow(TradeTariffBackend).to receive(:service).and_return('uk')
         expect { described_class.apply }.to raise_error TariffSynchronizer::WrongEnvironmentError
       end
@@ -226,7 +228,7 @@
     end
 
     context 'with uk service' do
-      xit 'will raise an wrong environment error' do
+      it 'will raise an wrong environment error' do
         allow(TradeTariffBackend).to receive(:service).and_return('uk')
         expect { described_class.rollback(Time.zone.yesterday, keep: true) }.to raise_error TariffSynchronizer::WrongEnvironmentError
       end
diff --git a/spec/unit/tariff_synchronizer/base_update_importer_spec.rb b/spec/unit/tariff_synchronizer/base_update_importer_spec.rb
index 18fc3efb7..9d3f95126 100644
--- a/spec/unit/tariff_synchronizer/base_update_importer_spec.rb
+++ b/spec/unit/tariff_synchronizer/base_update_importer_spec.rb
@@ -6,6 +6,9 @@
   describe '#apply', truncation: true do
     before do
       allow(TradeTariffBackend).to receive(:service).and_return('xi')
+      # Setting :FIND to NIL as Taric_Importer.rb checks a file doesn't exist to Proceed_With_Import?
+      # SEE SPECS ON LINES 39 & 58.
+      allow(TariffSynchronizer::TaricUpdate).to receive(:find).and_return(nil) # Assuming no existing record
     end
 
     it 'calls the import! method to the object' do
diff --git a/spec/workers/rollback_worker_spec.rb b/spec/workers/rollback_worker_spec.rb
index 982ad0e31..522380f4b 100644
--- a/spec/workers/rollback_worker_spec.rb
+++ b/spec/workers/rollback_worker_spec.rb
@@ -31,7 +31,6 @@
 
     context 'for uk' do
       before do
-        allow(TradeTariffBackend).to receive(:use_cds?).and_return('true')
         allow(TradeTariffBackend).to receive(:service).and_return('uk')
         allow(TaricSynchronizer).to receive(:rollback)
         allow(CdsSynchronizer).to receive(:rollback).with(date, keep: false)
diff --git a/terraform/admin_uk.tf b/terraform/admin_uk.tf
index b4a4c85c1..c709a34db 100644
--- a/terraform/admin_uk.tf
+++ b/terraform/admin_uk.tf
@@ -36,10 +36,6 @@ module "backend_admin_uk" {
     local.backend_common_vars,
     local.backend_common_worker_vars,
     [
-      {
-        name  = "CDS"
-        value = "true"
-      },
       {
         name  = "GOVUK_APP_DOMAIN"
         value = "tariff-uk-admin-${var.environment}.apps.internal" # This is necessary for a GOVUK gem we're not using
diff --git a/terraform/admin_xi.tf b/terraform/admin_xi.tf
index d2e543317..c9586d0bb 100644
--- a/terraform/admin_xi.tf
+++ b/terraform/admin_xi.tf
@@ -36,10 +36,6 @@ module "backend_admin_xi" {
     local.backend_common_vars,
     local.backend_common_worker_vars,
     [
-      {
-        name  = "CDS"
-        value = "false"
-      },
       {
         name  = "GOVUK_APP_DOMAIN"
         value = "tariff-xi-admin-${var.environment}.apps.internal" # This is necessary for a GOVUK gem we're not using
diff --git a/terraform/backend_uk.tf b/terraform/backend_uk.tf
index c3dba3d03..68b05bba6 100644
--- a/terraform/backend_uk.tf
+++ b/terraform/backend_uk.tf
@@ -37,10 +37,6 @@ module "backend_uk" {
   service_environment_config = flatten([
     local.backend_common_vars,
     [
-      {
-        name  = "CDS"
-        value = "true"
-      },
       {
         name  = "GOVUK_APP_DOMAIN"
         value = "tariff-uk-backend-${var.environment}.apps.internal" # This is necessary for a GOVUK gem we're not using
diff --git a/terraform/backend_xi.tf b/terraform/backend_xi.tf
index 42280d5af..e22ca595e 100644
--- a/terraform/backend_xi.tf
+++ b/terraform/backend_xi.tf
@@ -35,10 +35,6 @@ module "backend_xi" {
 
   service_environment_config = flatten([local.backend_common_vars,
     [
-      {
-        name  = "CDS"
-        value = "false"
-      },
       {
         name  = "GOVUK_APP_DOMAIN"
         value = "tariff-xi-backend-${var.environment}.apps.internal" # This is necessary for a GOVUK gem we're not using
diff --git a/terraform/worker_uk.tf b/terraform/worker_uk.tf
index a96241caa..9422fe1e3 100644
--- a/terraform/worker_uk.tf
+++ b/terraform/worker_uk.tf
@@ -47,10 +47,6 @@ module "worker_uk" {
     local.backend_common_vars,
     local.backend_common_worker_vars,
     [
-      {
-        name  = "CDS"
-        value = "true"
-      },
       {
         name  = "GOVUK_APP_DOMAIN"
         value = "tariff-uk-worker-${var.environment}.apps.internal" # This is necessary for a GOVUK gem we're not using
diff --git a/terraform/worker_xi.tf b/terraform/worker_xi.tf
index ebfd68b08..dd5701b81 100644
--- a/terraform/worker_xi.tf
+++ b/terraform/worker_xi.tf
@@ -47,10 +47,6 @@ module "worker_xi" {
     local.backend_common_vars,
     local.backend_common_worker_vars,
     [
-      {
-        name  = "CDS"
-        value = "false"
-      },
       {
         name  = "GOVUK_APP_DOMAIN"
         value = "tariff-xi-worker-${var.environment}.apps.internal" # This is necessary for a GOVUK gem we're not using