Ah - Windsor Blue.? It sounds so regal!
Car went in to the tried and tested local VW idependant garage yesterday. Conclusion: worn upper guide rail and/or tensioner.? Parts aren't too expensive (?140), but 4 hours of labour, so will probably cost ?300 all in. Not the end of the world, but a bill I could do without!
Anyway, the guys at the garage were great (been using them for years), they had all the exploded engine diagrams for me and all the parts listed so that I could see how the overall cost was built up.? In fact, they have been so good for so long that I'm going to post their details in the Good Guys section.
No more rattles on cold from next month!