Hey Paddy,
I had a similar problem with my A10 and I was quick to judge it as what I think is called induction bias, but it turned out I had a minor air leak at the carb flange that solved itself when I got a new o-ring for the carb and a new gasket - the old one had turned almost rock solid.
Andreas
Edit: I was a bit quick to drop the induction bias in here, but as I recall the A7 is not prone to that particular problem, but I'm sure some of the guys on here may be able to confirm if my memory serves me right.