Thanks for your reply, I just had a look at your two links, the first one is a really handy page but the second doesn't really mean anything to me as I have no clue about VCDS etc, but its somethings I can look into.
Are the tumble flaps something I can clean or is it a part that needs replaced? It mentions the tumble flaps are operated to enhance fuel/air mixture. I can get 38 - 40 mpg very easily ('05 GTI), maybe I'm not understanding but if the flaps were not working correctly, would my mpg not be worse?
The text after the codes in your first link differs to the description I get from my car but the code is the same, do you know what this means?
I'm sort of trying to avoid going to VW with it, I called them today and asked them if the could enlighten me but they were not very forthcoming with information and wanted to charge me 70 quid just to put the car on their machine, I'm not keen on that as you can imagine. The car seems to run perfectly with no problems at all and with no dash warning lights or anything, which is confusing.