Fixed another 1050 - one of its faults was a slack belt. Came up with an idea and it's worked. I removed the "tyre" from an old tape decks capstan pinch/pressure roller. Managed to fit it onto the motor pulley, then fit the belt around it. Small speed adjustment and now it's working fine. I would rather use a new belt but seeing as though they are hard to get them this worked a treat.
I would of put up a pic but can't do it from my mobile. I sent the pic to brenski - can you edit this post and put the pic up on here?