Robin if you do decide to change the water pump at the same time (and I agree it should be done) could you, if possible, take a look at the old/new parts and confirm whether the pump impellors are made of plastic or metal? Would be much appreciated 
I thought I heard somewhere that all water pumps now have the metal impellors!
Even with the metal impellors, it still don't stop them from braking free of the shaft, though.
....I've just had a chat with my man at my VW dealers and he said exactly the same - There used to be probs braking off the shaft when plastic and he thinks the Mk5 has metal impellors but didn't know for certain off-hand but we'd look and so I'll confirm here next week.
He also agreed that, although it wasn't on the servicing 'list', we should renew the water pump while at it and I'd only be charged the cost of the part.
Similarly the underfloor fuel filter is meant to be a 'lifetime' part but he changes his on his own cars every 2 years anyway and he said that with a remapped car running V-Power it was good maintenance practice. So, it'll be done too - It's only £25 and includes a 'regulator'.
Oh, and my dealer would be changing the coolant anyway and also be doing a pressure test. And they only replace the whole cambelt kit with rollers etc and wouldn't entertain just doing the rubber belt alone.
I think my car is in good hands and it's wrong that apparently not all VW dealers are like this.

Dare I say I'm lucky!
Thanks for your valuable input on this, T_T
