Hi there John I recently had the same on an old L reg model, same setup as yours... Some other garage had taken some £150. off the guy to replace the belt and tensioner with new, but it still squealed... and really badly/stuffed pig style. In fact the customer said it was worse than before. Not knowing any history on the car (other than what I just said) I ordered and fitted a new belt (im afraid I cant recall the no.s, and the 'recent new' one had worn off due to the slipping I presume ) - the belt was marginally smaller and im reckoning that that was it, made all the difference. Certainly no more squeals. So, I'd go for the belt as suggested.. Let us know, Mike