As I said : not cheap. I had my 1972 sunroof R4L resprayed many years ago and had little change from a £grand. The preparation is very fiddly and time-consuming. But you're probably talking, so long as the job is done properly, 20 years before it needs to be done again, so £50 p.a. is not much, really.
The important point is that you need to find a repairer who is committed to the whole Classic-Car business. With all due respect to "Paul Narramore" such a person is not necessarily going to be found in a garage dealing with BMWs. Emotional commitment to the job, without which you probably won't get something done properly, is in such a case far more important than mere money (within reason, obviously).
I'd suggest to "Brian" that he needs to put "Classic Car Restoration" into Google to be put in the right direction, rather than "Auto Bodywork".