diff --git a/lib/manage-prototype-handlers.js b/lib/manage-prototype-handlers.js
index 0aa7d2b7fa..154aca3ef7 100644
--- a/lib/manage-prototype-handlers.js
+++ b/lib/manage-prototype-handlers.js
@@ -119,7 +119,7 @@ function postPasswordHandler (req, res) {
   }
 }
 
-function managePluginsMiddleware (req, res, next) {
+function managePrototypeMiddleware (req, res, next) {
   const { scripts: frontEndScripts } = getScriptsAndAssetsConfig(getInternalGovukFrontendDir())
   const { scripts: kitScripts } = getScriptsAndAssetsConfig(packageDir)
   res.locals.managePlugins = {
@@ -744,7 +744,7 @@ async function postPluginsModeHandler (req, res) {
 
 module.exports = {
   contextPath,
-  managePluginsMiddleware,
+  managePrototypeMiddleware,
   setKitRestarted,
   csrfProtection: [doubleCsrfProtection, csrfErrorHandler],
   getPageLoadedHandler,
diff --git a/lib/manage-prototype-routes.js b/lib/manage-prototype-routes.js
index 24d2ecc2d1..ff4b52ad39 100644
--- a/lib/manage-prototype-routes.js
+++ b/lib/manage-prototype-routes.js
@@ -6,7 +6,7 @@ const express = require('express')
 
 const {
   contextPath,
-  managePluginsMiddleware,
+  managePrototypeMiddleware,
   setKitRestarted,
   csrfProtection,
   getPageLoadedHandler,
@@ -36,7 +36,7 @@ const { govukFrontendPaths } = require('./govukFrontendPaths')
 
 const router = require('../index').requests.setupRouter(contextPath)
 
-router.use(managePluginsMiddleware)
+router.use(managePrototypeMiddleware)
 
 function getAssetUrls (pluginDir) {
   const { scripts, assets } = getScriptsAndAssetsConfig(pluginDir)
diff --git a/lib/utils/index.js b/lib/utils/index.js
index ca3f4f6456..77239d9530 100644
--- a/lib/utils/index.js
+++ b/lib/utils/index.js
@@ -253,7 +253,12 @@ async function searchAndReplaceFiles (dir, searchText, replaceText, extensions)
   return modifiedFiles.flat().filter(Boolean)
 }
 
+const managePrototypeCache = {}
+
 function getScriptsAndAssetsConfig (pluginDir) {
+  if (managePrototypeCache[pluginDir]) {
+    return managePrototypeCache[pluginDir]
+  }
   let {
     assets = [],
     scripts = []
@@ -267,7 +272,8 @@ function getScriptsAndAssetsConfig (pluginDir) {
     scripts = [scripts]
   }
 
-  return { assets, scripts }
+  managePrototypeCache[pluginDir] = { assets, scripts }
+  return managePrototypeCache[pluginDir]
 }
 
 function sortByObjectKey (key) {