Before anyone suggests it no I don't have a small bird living in my engine bay... :D
This has been going on a while, sounds like it is coming from the right hand side of the bay and the pitch alters with the speed of the engine (faster = higher pitched, slower = lower pitched)... It's literally...
Last night I developed some weird noise from under the bonnet? It kicks in at about 2500-3000 rpm and carries on throughout. If I fully rev it, when I lift off there is a high pitched squeal.
Hoping that It's not a big issue anyone got any ideas?