Nice car, I think yours may be the same colour as mine, "VW black magic".
Did you ever sort the alternator noise? Basically you need to stop the insides from moving while you try and turn the pulley, it should only move one way (one way bearing installed).
Yes you can get a replacement clutch only, you can get them from GSF for about £30 and then you will need a special tool like this one (
http://www.ebay.co.uk/itm/BOSCH-ALTERNATOR-CLUTCH-FREE-WHEEL-PULLEY-REMOVAL-TOOL-/310181570394)
The bit that moves loads is the tensioner I think. It just maintains belt tension so it will move a bit, that is normal.
One question if you don't mind, what size are your tyres and what is the recommended pressure for them?
I have a tdi with the starfish alloys (as a modification) but am convinced that my tyres (225/45 17) are too wide.
The car looks really good overall, the door cards look very smart.