Update for anyone experiencing similar problems.
The culprit was the SH5.EXE.
Went into properties and changed the compatability DPI settings. Also changed to administrator.
Loaded up the vanilla game sucessfully.
I then copy/pasted everything from my previous install including TWOs to the new folder.
I then copy/pasted my User data old save files.
TWOs booted up perfectly.
Many thanks to you all!