As far as bodywork goes, I had some good work done on my MX5 sill by a chap, who I forget the name of, at Brooklands garage in Truro, but he had moved to work at TMS garage in Threemilestone when I happened to spot him last year. Old School hammer and a bit of wood rather than resorting to repair panels, I think he was only doing a few days a week nearing retirement. I have heard good things about Spraytech in Penryn, but my experience with them is limited to a small MOT patch on my Alfa and seeing lots of nice cars in there... Maybe worth a visit and a chat with places and just seeing how enthusiastic they are? I expect the mention of a Lancia Beta will instill either fear or intrigue.
Good luck anyway, and hopefully I spot a Beta around (The IE is hibernating, but may come out before its tax exempt next year)
Felix