I managed to get the thing apart but couldn't undo the centre nut on the roller as 19mm didnt fit for me, but the plastic gear looked in okay condition.
Made a new clutch out of 3mm gasket cork and refitted everything and was expecting it to work.
The new clutch bit in okay but still didnt have drive, will try again tomorrow.
Think I will have to dismantle the end to get a closer look at the plastic gear
If you want to dismantle the clutch just hold the spline end in a vice and make a special tool that enters the holes in the other side and unscrew it, it's a left hand thread so unscrew in a clockwork direction
