tensioner and beltWhat have you had replaced?
Could be the clutch on the alternator pulley. Ive had same problems and fitted new tensioner and belt which solves it for a while but then the noise comes back. Been told its a common problem so ordered a new one today. I will post back once ive fitted it and hopefully sorted it.
Problem solved. It was the pulley. I took the alternator off and took it to a specialist because a vw tool is needed. £5 later all sorted.