Thank you for that Bruce and Darryl, it helped heaps.

A couple of things it has highlighted, I need to replace a couple of bits and I don't have bolts on the end of part 20, I have studs with nuts.

When I examined the exploded view I realised I was working the wrong end of 21 and have now levered the "captive" end instead of trying to hammer from the nut end. This allowed the rod the be withdrawn and the roller to be removed. Part 21 and the end caps (part 33) are beyond servicable life and I need to get a price for them if you could point me in the right direction please.

The other thing is part 20 which seems it will need the side plate to be loosened to allow it to "flex" out tof the way to remove the part. Once I get it out I can properly ascertain if the studs are removable, and therefore replacable, or if I need to do that everytime. Although I doubt it would need to be removed very often. There is a fair amount of wear in the ends of that too so I may need to bush them but I will have a think about that once I get it out.

Your help is appreciated.

Cheers,
RossA