Well, 18 months later and the front N/S needs another refinishing.....this time a series of minor "kerb kisses" mean that about 270 degrees or rim needs refinishing.
I took the wheel off, started rubbing down and thought "this needs quite a lot of work, leave it to a professional" so I took it round to a specialist and for £120 inc VAT they completed the work in 3 days. Tyre off, media blast back to metal, prime, paint, clear coat.
The colour match is perfect.
The workmanship is better than mine.
I thought about getting all the wheels re-finished, but the other 3 are OK, one or two minor blemishes.