UK Car Repair: Rover 200 Auto - Whirring Noise, rover 200, pulleys

Question
Hi, I have a V reg Rover 200, automatic.  Recently it has started making a whirring noise that seems to be linked to acceleration. I have checked the timing and fan belts and they seem fine.  One other thought was the alternator bearing, but I am not sure.  Although it could be unrelated, the tick over revs seem to have increased to over 2000.  Any ideas what might be causing this?

Answer
What year is the car? Unless you can probe it with some type of stethescope the only answer is to remove the drive belts one at a time until the noise stops. If there is only one belt, then with it removed, start the engine and see if the noise is still there, if not, switch off the engine and spin the various pulleys and listen for the noise.