OK, thanks.
This is what how far I have got.
There is a collar on the left side of the spindle held by two grub screw. Unscrewed that.
Next there is a flat plate held by eight allen bolts which I removed and can see the rear roller bearing.
Loosened the grub screws on the pulley assembly. The pulley assembly will then slide to the right about 3/4".
If I push the spindle to the right, it will move till the main rear bearing re-contacts the pulley assembly and then it's solid.
It seems as though the rear bearing is fixed to the spindle in some way, but I can't see anything.
I'm baffled, to be honest.
David Lloyd