Hello, latest on the mystery noise coming from the above A3, found out that it was the rear tyres that although weren't worn down were feathering, thus making a droning sound when cruising, put new boots on and sounds great again. apparently its a common problem on all V.A.G group Vehicles. 

Many thanks Peter. 
Feathering can be a sign of alignment issue.

I wonder if you have had alignment checks and adjustments - if necessary - carried out, now you have had new tyres fitted. 
Kind regards,

Gareth. 

Thanks for your reply , no my tyre centre didn't mention alignment check but I will contact to check, thanks for your advice. Regards, Peter.