Any updates on whether these issues have been sorted?
Luke
I believe mine is finally sorted.

First off the cam belt, tensioner and backing plate(

) was changed, this didnt solve it so this was all removed so the water pump could be replaced.
Whilst this did improve things I still wasnt quite happy with it, so back it went, to have the timing chain and tensioner changed. I think it was this that finally sorted it. At this point the oil and filter were changed too.
As I have been without the car for 2 whole weeks (mk6 1.4 TSI as a courtsy car, nice motor good mpg and refined but it isnt a GTI) its difficult to say for sure but it does feel as though its running better and pulling harder.
I suppose that if the timing chain was at fault then it would have affected the valve timing and in turn effect performance?
Luckily all this work plus 2 monza II's and 4 centre caps were replaced under warranty which ran out on monday!!!
The service I recieved from my local VW dealer was 1st class I cant fault it at all.