Have you got a reg and some pics of the car? If you have PM me them and I may know the car and may have some accident pics.
There was a forum members car not so long ago in black that has been repaired.
If a car is repaired properly then there should be no issues. I would arrange for a garage to carry out a full inspection close to where the owner lives prior to purchase, but you should ok this with the owner first and if he agrees it may be that there is nothing to hide