diff --git a/malcolm/modules/pandablocks/controllers/pandamanagercontroller.py b/malcolm/modules/pandablocks/controllers/pandamanagercontroller.py
index de9371085..209f9944a 100644
--- a/malcolm/modules/pandablocks/controllers/pandamanagercontroller.py
+++ b/malcolm/modules/pandablocks/controllers/pandamanagercontroller.py
@@ -1,4 +1,5 @@
 import json
+import re
 import time
 from typing import Any, Dict, Sequence, Set, Tuple
 
@@ -325,6 +326,6 @@ def set_layout(self, value):
             else:
                 self._json_layout.pop(name, "")
         if self._json_layout != old_json_layout:
-            self._client.set_table(
-                "*METADATA", "LAYOUT", [json.dumps(self._json_layout)]
-            )
+            # Custom encoding so the lines aren't too long and there aren't too many of them
+            lines = re.split(r'(?<=,) (?!"y")', json.dumps(self._json_layout))
+            self._client.set_table("*METADATA", "LAYOUT", lines)
diff --git a/tests/test_modules/test_pandablocks/test_pandablocksmanagercontroller.py b/tests/test_modules/test_pandablocks/test_pandablocksmanagercontroller.py
index 16b23c23c..9f07536f0 100644
--- a/tests/test_modules/test_pandablocks/test_pandablocksmanagercontroller.py
+++ b/tests/test_modules/test_pandablocks/test_pandablocksmanagercontroller.py
@@ -269,7 +269,10 @@ def test_layout(self):
             [
                 (
                     "*METADATA.LAYOUT",
-                    '{"COUNTER": {"x": 1.2, "y": 2.3}, "HDF": {"x": 3.5, "y": 4.1}}',
+                    [
+                        '{"COUNTER": {"x": 1.2, "y": 2.3},',
+                        '"HDF": {"x": 3.5, "y": 4.1}}',
+                    ],
                 )
             ]
         )
@@ -287,8 +290,8 @@ def test_layout(self):
             "*METADATA",
             "LAYOUT",
             [
-                '{"COUNTER": {"x": 1.2, "y": 2.3},'
-                ' "HDF": {"x": 3.5, "y": 4.1},'
-                ' "TTLIN1": {"x": 0.0, "y": 5.6}}'
+                '{"COUNTER": {"x": 1.2, "y": 2.3},',
+                '"HDF": {"x": 3.5, "y": 4.1},',
+                '"TTLIN1": {"x": 0.0, "y": 5.6}}',
             ],
         )