Re:
usual suspects,
bob jackson in leeds, good for single colours i think and reasonably priced, although their "wet paint" is fragile
argos in bristol, more expensive than bob, have found their stove enamel work to be good but they drag it out and they never phone to say it's done
tjc in bristol, used him for my 07 clockwork repaint as it was looking tired and it was spot on
fat creations, Ali is amazing, he is more expensive than most but the quality is spot on, he paints for a lot of the uk's top frame builders, aswel as the custom stuff for steve peat, renthal bars, danny hart etc, he also painted (well lacquered) all the hope technology frames, he seems to be the custom paint go to guy at the moment
there is also cole coatings workshop, they paint the frames for saffron frameworks and they are really lovely
also TA paintwork, (tommy450 on instagram) he paints Demon Frameworks as well as a few other top racers bikes, he did the transition bikes for the world cup if memory serves
cue the next person who says "i take it to my local powder coater and he does it for 20 quid" yes, it can be done, but it's always a basic job and they don't clean and tap the threads after they shot blasted it then painted the grit in to the threads which ruins the thread taps when you then have to spend hours cleaning them out. a good painter will send the frame back ready to build with minimal frame prep. also i'm betting Jez doesn't want a basic job.