And trust me, it's worth either going to someone you've seen the work of personally, or travelling a bit for the privilege of quality. It's fine if you don't mind a 'rough it'll do' kind of job, but if you're wanting to cut out and replace metal, I'm guessing you really want a job indistinguishable from the factory. There's just so many arches out there done badly, and it just seems a waste of time, to me. Had similar work done on a classic car once, and it was around the price mark Webby has suggested. If you say £80 spraying per panel, that leaves £120 per side for the metal to be cut out, welded in, smoothed until undetectable.
Remember, almost any idiot can do a rough job, then skim over with filler until it looks nice once painted - but if they're that level of bodge, they'll probably not let the filler properly cure, until the paint starts to fall off after a few weeks, or something similar. Again, all I can say is quality, quality, quality - it always pays. (which is not the same as paying a lot of money - expensive and quality are two different animals)
If you can find the local bodyshop that does insurance repairs, they're a good bet. The best in our area repairs damage to brand new, unregistered cars, freshly imported. (what's that? - I hear you cry - I might buy a brand new car, paying tens of thousands of pounds, and it may have had 'touch-up' work done, and the Manufacturer/Dealer didn't tell me? Yep.)