Remove both sides of the machine, you don't need to remove the back. Undo the screw at the back of each of the side rails at the top, the front of the machine will then tilt forwards and you can slide the new belt over the drum from the front.
Unclip the white plastic cover on the right right hand side of the machine (looking from the front) at the bottom and remove it to access the cylindrical plastic fan on the end of the motor shaft. Grip the spring clip holding it in place with pliers to release the pressure then remove the clip and slide the plastic fan off the spindle. You can then loop the drive belt over the shaft and work it backwards towards the motor - don't slip it between the jockey wheels yet.
Replace the spring clip onto the fan and squeeze it with pliers and slide the fan back onto the motor spindle (note that there's a flat section that must be lined up). Once it's completely home let go of the clip then replace the white plastic cover. You can then get the belt lined up properly with the spindle and jockey wheels.
Job done! Line the drum up on the front aperture and refasten the top side rails, replace the sides and off you go.
Bob, September 2008