A4 B6 2003 1.9 TDI.
First time in ages turned off the cd player. Apart from silence, a strange knocking sound was coming from the rear passenger side while driving. Especially noticeable over bumpy roads/small potholes. Looked in the boot for anything loose, all seems ok including spare tyre and the locking nut for the wheels. Had a look in the back seat for any interior trim funnies/seatbelt etc. All seems fine. Even went to local kwik-fit (gud idea?!) to check underside of car. Said all seemed fine i.e. bushes/exhaust/etc.

Sound still there. Anybody got any ideas? Might take to local ******* and get a roadtest with one of their 'technicians' along for the ride.

Cheers.