hi @hardingnick001
The files are all here in Visual Studio 2022 UE5.4.3 source Edit → Find in Files → Find All
Note the sub-search color
To install source for 5.4.3
git clone https://github.com/jimshalo10/UnrealEngine-5.git --depth 1 -b lgpu542 ue5LGU543
Follow instructions in
UnrealEngine-5/README.md at lgpu542 · jimshalo10/UnrealEngine-5 (github.com)