It's a pity you're not further south, but for the possible benefit of anybody else I've found a brilliant place in Sheffield - Shaw Motors Ltd, Loxley Road, Sheffield S6 4TE (0114 234 7604).
On my Fiat Bravo two-door (metallic pale blue), which is the office runaround, they filled and resprayed one side of the front valance which had been kerbed, filled three or four quite bad gouges (each six or seven inches long) on the big panel behind the passenger door which I had scraped on the stone wall of my son's house, repainted the panel and merged the paint job into the door to disguise a very, very slight shading (the downside of metallic).
They've done an absolutely stunning job - it is literally like new. The whole job cost £340 including VAT, and it would have been £70 less if I'd been content for them not to do the door as well.
I'll certainly use them again if (hopefully not) I need to. I'd be quite happy to let them loose on my Arctic silver BMW.