Yep, I was given an extended 1 years full parts and labour warranty when I bought the car (funnily enough standard 3 yr warranty has just run out !).
Spoke to the dealer after work and took the car straight down there. They did some tests and said something strange came up - like a rogue fault. They did a system reset and the light went out. They took it for a run and found no faults.
They sent the details off to some techies (they'll get the response tomorrow as it'd gone out of hours). If it's anything dodgy they'll call me back in. If the light comes back on then they've asked me to take it back in immediately and I can have a courtesy car while they run more tests.
Now I've been able to check the owners manual, the light staying on is to do with the lambda sensor - so it must be to do with a poor air/fuel mix. I'll keep my eye on it.
Definitely considering a VAG-COM though...would be really useful I think.
Daz