I've been quoted £100 + VAT, which is a special price as my girlfriend handles all their advertising & web presence. That includes sanding back, filling (if needed), primer, respraying and clear coat.
I was quoted anywhere between £120 - £350 by various companies, but they get very good reviews and gave me by far the most comprehensive reply to my photos and a very thorough explanation of the likely damage and solution.
They aren't doing the whole bumper, just the lower section and reckon it can be blended in with the top part of the bumper as most of the damage is on the underside.
I'll post a couple of pics later this afternoon after work, can't wait to get it looking like new again. I've bought a Karscher washer, clay bar kit and various other "detailing" products in preparation for the weekend.