Hi chaps

I usually lurk on here as I frequent UK forums but I am really stuck with this noise and was hoping someone on here might of heard it before.

Its intermittent and only does it when warm, I caught it on vid last night but the vid is not great, its a vibrating noise and is most audible at 2.5K rpm

It does it under load or in neutral, the car is a H22A8 Honda Prelude with 62K, cambelt and balancer belt changed 5K ago

I have tried to find the noise from under the bonnet but I can only really hear it from in the cabin, the engine seems to drown the noise out when under the bonnet

It only started making the noise two weeks ago

Any ideas please?

Thanks

http://img531.imageshack.us/my.php?image=mov00046nj9.flv