Hi I've a 2008 A3 TDI QUATTRO with a very annoying knocking/ rattle mainly on the O/S rear quarter, this only happens on uneven roads smoother motorway type roads it seems fine or if these some weight on back seats/ boot. I've checked for all the usual loose things and the garage I use has said everything is fine. Hope this is a common fault that someone has come across before I start spending a fortune on a lucky dip parts replacement.