Thanks guys - yes they are unmolested original RAs in superb condition apart from the small area that needs touchng up. I have currently left the silver on - it does not look too bad. The wheels are in such good condition that it would be rather OTT to have them all resprayed - I am a tight Yorkshireman anyway.
Am I best spraying the area, Thom rather than brush it in. The defect is about the size of half a slim finger.
Cheers.
Sounds like it should be an easy repair, spray it if you're confident, use the Mercedes colour that I have mentioned, and if it really is the OE paint, the Brilliant silver will be an almost exact match, just do a local repair to the affected area, You'll only need etch primer if you rub through to bare alloy, otherwise an aerosol of acrylic white primer will do you, cover it with a small blast of silver, leaving a couple of mins between coats, then a couple of light coats of lacquer to finish off
Use Grey Scotchbrite to key area's to be painted/lacquered, and mask the wheel center to avoid painting the whole wheel
If you've used any type of tire shine recently, then this must be cleaned off thoroughly! use lots of painters de greasing solution for this, everything is available from Halfords
Thom