Techie, your opinion please!

[Rich00p]

So a few weeks after getting my PD130, I started to hear a low down 'rumble' coming from the front of the engine bay at idle, this was followed shortly afterward by a sort of clicking / squirting noise when I turn the ignition (intermitant)
and now finally I get 'ALTERNATOR WORKSHOP' light come on accompanied by the battery warning light.

Now I just assumed my alternator is buggered and needs replacing, however I've done a search on vw/audi forum and it seems to be a fairly common issue concerning either the regulator or the alternator clutch or some part of the pulley not being tight enough, would either of these require a new alternator?

you don't happen to know what the squirty clicking noise on ignition is also?

I only ask as I don't want my garage replacing a perfectly good item if they don't need to

thanks in advance for your oracle like advice