Fabia VRS 5th gear rumble/Grumble

Hi Guys,

I have just joined up. Had my VRS since March 11. I love it 5 door pocket rocket on a 04 plate with 112k when I bouight it.

Had to replace all corners with Avon ZZ3's (The P-Zero's on it were about done and in my opinion are ****).

Anyway cut to the chase. In 5th get a nasty growl/rumble when coasting with the clutch engaged. Only in 5th which is weird..... Don't think its the clutch as I have had a clutch go before and slippage is more obvious than Gibraltor tacked on to Spain.

To put it simple as long as you have your foot on Accelerator in 5th, no noise. Take your foot off.... noise, put it back on noise goes. Put clutch down, noise goes. Any thoughts would be appreaciated as I (when I say I, I mean brother in law) like a bit of DIY. Also about to do 118k service, anything we should look out for and would vented discs and Green uns pads make much difference to the **** brakes?

Any thoughts?