I'm wondering the same thing. Have my 18 month service at litchfields in april so gonna get Iain to take a look then. He did mention there was some play on it last service and to keep an eye on it. At the moment its no louder than any of the other rattles/noices the beast makes anyway so not too concerned.
Sold: White R35 2010 Black Edition
Current: R32 - Nur engined - KH2 - TE37s