Ok a bit of an update. I migrated to the standalone version. Did a successful repair and I am still getting a crash loading Marianas. Here is the latest logfile.
The process I followed to ditch Steam is below for info. This all worked fine.
Edit: I've also tried a few other aircraft and maps I downloaded and have had lots of crashes and errors. Is it worth a total uninstall and reinstall? I can't get The Channel map to run either.
Download installer from ED
Untick "download" at end of setup
Copy across files from Steam to Standalone
Change STEAM to ED in retail.cfg
Run Repair DCS World (don't delete any files yet)
Start the game, activate the modules you want, and run Repair DCS World again
dcs.log