Grinding noise at high revs

[ncfc-canary]

Hey all. I've been an owner for about 4-5 months now but not found time to login and say hi much.

I'm having a problem with a noise at high revs and hope someone can help. Whilst in second or third gear all is fine until I reach about 4-5k revs, then along side the sound of the revs theres this strange grinding noise. It sounds like a metal plate rubbing lightly against something else so I suspect something has come loose.

It doesn't always happen however and no other noticable performance problems occur as a consequence (i.e no drop in power, no judders, squeals, gear box whines, no smoky turbos) and the power delivery is still as smooth as expected. The car has also only done 44k in 11 years (came with FASH so should be genuine anyway) so it may not be not something that could be associate with high mileage.

Any ideas appreciated. If you need additional info let me know. thanks