Just to update on this.
As this issue has been intermittent, it has been difficult to diagnose.
Finally yesterday my local service centre informed me that the clutch was faulty and required a new clutch repair kit. Although it will be carried out under warranty the cost was £1,500 plus car hire!!!!
The car is 11 months old been driven carefully and well looked after and only covered 6,000 miles!!
I have booked it in to have the work carried out and have written to Audi to complain as this has come as a real shock as I thought that buying a premium brand car would provide many years of carefree motoring, now I am not so sure.
I will keep the group updated.
Tony