Cheers for the replies.

Plug gap not been changed since fitting the turbo. What should gap be for this spec??
Be due new plugs anyway before it sees the road next month.

Chip should be capable of stage 3.... Well, so i was told when the car was uprated to stage 2, which was carried out by AVA. I will double check with them tomorrow.
Problem does seem to be pointing at this, by the replies.

Martin; Fuel pump has been fitted for a while, but car has not done a lot of miles since. Will check filter tho.

Stu.