Can anone suggest a good car bodyshop in london (fix rusty wheel arches)?

I have a 1992 volvo 480, it is in immaculate condition except for the onset of rust around the rear wheel arches. I am looking for a bodyshop in london (ideally north) that could carry out a repair or if necessary replace the arches. Please help me save this rare car from the evil rust! Thank you in anticipation.