Cheers for the reply Paula.
It is very odd, at the end of the day a 10w bulb is a 10w bulb and if they give off too much heat for the holders (remember the standard ones are 5w) then it should have been a problem for everyone or nobody.
Mine were not that bad actually likely because I removed them after a couple of weeks, there was a post I dug up and a lad had to change out the whole rear handle unit as they had melted so bad! Could have been a lot worse, I'm sure that would have caused a fire if left for long enough!
Anyway I've worked out there's two solutions:
1. Try and code them out with VCDS, some of the later S3's (2010+) have the ability in one of the modules to turn off the bulb checking for the number plate lights.
2. Buy some genuine Audi LED's from the A4, A5, A6 and fit them along with one of these:
AUDI LED Adapter Kennzeichenbeleuchtung für Audi A3 S3 RS3 8P A4 S4 RS4 8E B6 B7 | eBay
One or the other will get them working on a 2010+ S3 it seems.
Going to check the module on my own car tonight and see if they can be coded first, if not then that Ebay item it is