Philips 14cf1014 Comp+RGB mod help

[Dagare]

This is my first post here so sorry if this is in the wrong section etc.
I've been trying to mod my Philips 14cf1014 for composite + rgb input. The TV is not hot chassis, the ic datasheet shows it handles composite + rgb and that there was a version of this tv with a separate circuit board for comp+rgb in/out (philips 14cf1114).
I've tried creating a modified circuit board based on the schematic included on the service manual, removing the vid+audio out, replacing the din plug with a scart plug and adding audio passthrough for external speakers, but I could only achieve audio passthrough and video blanking, no audio or vid from the tv.
I know I should probably separate the grounds to prevent ground loop for audio at least and I'm sure there's plenty of optimisations that can be made, but any advise for what might be wrong with my designs to prevent it from showing any image would be greatly appreciated, I'm still quite new to this level of modding (please ignore the backwards audio passthrough, I manually fixed this with jumper wires).
Link to the service manual I'm using:
https://freeservicemanuals.info/en/s...None/None/CF1/