My mission for this week is to stick this on Ebay, but thought I'd check if it's of any use here.
After much research I bought the a set of Whispbars and they are indeed very quiet and easy to fit into the roof rails. They were so good I got a second set which have never been used and are still in the sealed box. This is the flush mounted roof bar set with footpack suitable for the 2009-2015 Audi A4 avant roof rails. Compatible with Thule attachments such as ski racks and bike racks.
May be suitable for other cars, check the whispbar website if you need more info.
http://www.whispbar.co.uk/products/4/flush-bar
£180 from the roofbox company, looking for £120.