Indeed,
Best case for my starting point is an original, stock healthy car, I also always like to work from the original file in a car rather than a "best, closest file" that I can get for a million and one reasons.
I'll talk so sedox if you don't mind and ask them if they will give me the original from your car if you don't want to go back or they won't put it back to original for you.
I may be able to work on your car via the OBD socket but I'd be very surprised if they have left the access to the ecu "unlocked" for anyone else to look at which means ECU out etc.