Thanks guys
It seems to me that at least the bolt should be available free issue. I have been qouted £300 odd quid for a full set of pulleys etc from the dealer. Not sure why I would need all that. Since fitting a new belt and vented cover some 10,000 miles ago there have been no isssues and belt looks as good as new.
Not sure how a new bolt helps things. Does it have some sort of tab washer fitted. Pics would be good if anyone has them. I am going to ring the s and s guy
In Wales and see what he has on offer.