Could only ever recommend
http://www.dent-tec.co.uk/ - Wigan based but well worth the travel.
Through my family we have had 4 dents/bumps ever needed doing and none of them have ever been finished to a standard of that you'd be totally happy with - always a bit dull, not smooth etc. - but that serves us right for always seeking out for the lowest bidder.
I decided to get my Audi done properly after a car park bump, and took it to dent-tec in Wigan. For a CD sized bump it was just under £200 - so not the cheapest.
But it was immaculate afterwards - 100%. If you or anyone have previously gone through the pain of trying to find someone who will actually do a body good job then I know these guys will.
Just a thought.