I've been intouch with a local mobile bodywork/wheel repair company in Cambridge, who tell me that they do wheel refurbs for about Ł50 each.
However, they don't take the wheel off the car, and only refurb the outer face. They tell me that this is normal practice with wheel refurbishment.
I thought most places take the wheel off the car, and remove the tyres, and refurbish the whole wheel (inside and out).
Anyone with any experience on this?