cheers mate but have an update. AA man threw me curve ball. got the ever so slightly used drive belt off and gave the pulleys a quick spin, all fine and dandy no grateing no crunching but the drive belt tensioner is locked solid! also what looks link a 2 inch diameter black plastic ring tangled up between belt, tensioner and block. so I think i found my culprit. picking the bits up 2morrow AM so i'll let you boyz know how i get on