Just thought I'd put up a quick post to recommend a local scratch repair guy. He mostly does work for the dealers, Audi / VW and Mazda but also does a bit of work for individuals.
A friend of mine had a 6-8" dent with broken paint etc on the rear arch of his MK4. He has done a quality job of the repair, you really can't tell the work has been done. He also touched up a couple of other minor marks for only a little more. He did such a good job that I've got him booked to tidy up my S3 next week.
He's based in Warrington / Liverpool and called John. 07958 502 059 Let him know Andy gave you the number and I'm sure he'll do you a good price.
I'll get up some picture of the S3 before and after once he's worked his magic!