Just thought I would share this in the hope it helps someone else.
My MK5 developed a rattle caused by the plastic above the CD player squeaking during driving. Had a similar problem on my MK4 a long time ago which was fixed under warranty. When I got the car back from the dealer I noticed that they had used some felt tape to "seal" some gaps between the plastics which was causing the noise.
Anway was in the local VW dealer at weekend and mentioned to the parts guy that my MK5 had developed a rattle and did he know where I could get some of the tape which was used on my MK4. Nice guy that he was he handed me over a roll free of charge. It worked a treat. Its like double sided sticky tape but one side is a thick felt and other side (under the yellow tape) sticks to the car.
Part number is 533 863 288 A (labelled "Filzstreif" on the packet)
