Did you put it into a VAG sort of garage to get a service? I'm surprised that the garage that serviced it, VAG or otherwise, did not comment on this if they thought anything was not right. Might you it could have been AC that did the work for you!
 
No i took it to a local VAG independent specialist, i specifically asked him if he found anything wrong with my car and he said 'no, your car runs a treat'. So i am wondering if they have used the cheap spark plugs or something? BTW Arnold Clark were not too bad the other day with me, took it in for a annoying creaking noise i have been getting for ages, took the car out- no creaking (just my luck!). Anyway, techie puts car on ramps to discover that the dealer i went to to get the bushes replaced, had made a total f*ck up of it, one bush was not sitting inside the casing properly and had been smashed with a hammer and had no grease (Bickets, Kilmarnock- nice work NOT!) Anyways will be getting sorted tomorrow and i have a brand new Ibiza Sport as the courtesy car (free of charge of course) Rant over lol!
 
Strange, I'd doubt if a proper VAG indie would use cheap plugs - or at least plugs that would cause problems quickly - that would give them a bad name and play into the hands of the main dealers. Good to hear that AC can do a good job, my daughter has never had a problem with the local Seat one (yet). I have heard that Bicketts are not too good in general though. Mind you I've also heard accusations about my local VW main dealer that I use for MOTs - so I hope that is wrong information!

Still none of that solves your problem - maybe ask AC to comment on it!