Never used them myself but heard Pristine wheels in Milton Keynes is really good . Alloy Wheel Repair Experts, Alloy Refurbishment
depends on the erea and how much you're planing to spend, powder coated will be better than cheap solvent
They don't work on buckled or badly damaged wheels... Unless you go there in person waving cash in their face. Kind of expensive, and not the best anymore. I've used Rimtec which are a mile from Pristine, just as good, and much cheaper, although they can't do welding. Mint alloys seem to have good standard of work and there's loads of examples on the Facebook & Twitter accounts.
Who's that then? Wheelgenie were the only place Ive found that will rebuild chewed up lips by welding, they did a lovely job on my rears after they got mullered by a tyre changing machine.
There's a guy called rusty rims on Facebook who I have been talking to he done a set of my mates wheels
This guy does everything https://www.facebook.com/pages/Maverick-wheels/249433151815616?hc_location=stream He fixed one of my rims on my 3 piece works when i bent it , good fast and friendly service too