In my experience of 30 years of dealing with rusty arches on various cars ive owned, once they bubble like that its really hard to stop, You can repair them by grinding and using rust treatments and then filler but you are always playing a waiting game for it to come back through. It may last a year or it may last a few weeks. The only way to stop it for good it to fully cut out the rust and weld in new steel then cover the rear of the repair area with cavity wax so air and moisture cant get to it.
Id say you want at least 5k off the price and thats assuming the rest of the car is immaculate. I wouldnt let them do the repair either, you need somebody with experience in repairing classic car bodywork who is used to dealing with this kind of work.
Id say you want at least 5k off the price and thats assuming the rest of the car is immaculate. I wouldnt let them do the repair either, you need somebody with experience in repairing classic car bodywork who is used to dealing with this kind of work.