I don't want to get into a 'they ripped me off' thread but believe me the two firms mentioned are the best in the country. There are loads of paint shops dotted around the country but most rise up and fall over within a couple of years. One new boy on the scene has been offering bargain prices recently but it won't be there in a year or two because they just don't charge enough for the very labour intensive job they are doing - if they do it correctly.
Mick Allen does the fleet I look after, our customer aeroplanes and my own and you won't get a better job done elsewhere if you want value for money.
By value I mean an excellent, long lasting paint job - not one that will start to flake off or allow the corrosion back in a year.
As I said you pay for what you get. Can you go and see a ruck of aircraft this firm has painted over the last 5+ years and see how they look? No point flying half way across Europe and paying half price if it lasts only a year or two, is it? Mick Allen keeps his machines on his website so it's pretty easy to see what he has done and go burning holes in the sky to have a look at them now. Have a look at:
http://www.allenaircraftresprays.co.uk/ And no I'm not on commission - they don't make enough money to pay it!
One European firm recently did the big Cessna 421 SIDs for a good price. Wasn't that good when a UK firm inspected it and found most of the work (like taking the wings off!) hadn't actually been done!