Hi again,
Thanks for the pointers. I had a really fun time working through my mods folder.
My problem was traced to the SU30 EFM mod by Codename Flanker Community. The specific mod version in question was v2.7.43 Beta.
I removed the SU30_EFM from the SavedGames Mods/aircraft folder and re-started DCS. The A-10C II cold start now works ok.
I did not investigate the problem any further (since I only tried out the SU30 once or twice).
Thanks again, and case closed.
Kind regards,
Paul
paulw10's post in A-10C II crash was marked as the answer