(G) JTD alternator bearing failure?

Just been having a look at a friends JTD mk2 punto for them as they said that it was "louder than usual".

As soon as I started it I could hear a different noise than usual. Popped the bonnet and the rather loud noise appears to be coming from somewhere in the vicinity of the alternator.

The noise is affected in frequency by engine speed and not affected by road speed or engine temperature. It sounds like a grinding noise and, although i've never heard one before, sounds to me like what a failing bearing would sound like.

Much as I would like to, I currently don't have the time or experience to attempt to fix this, so I am really looking for advice as to what the garage I take it to should check, and what are the likely costs involved for the fix, to make sure that he doesn't get ripped off.

Any help appreciated
Thanks

Any ideas? I need to take it to the garage this morning.

Take the alternator belt off and see if the noise goes away.