Thank you for the further comments on tool design/selection. The thread has wandered (as they do) but for me it's all useful information as I set myself up to use the lathe rather than just fix it.
The C spanner has arrived, the spindle has been removed and the bearing realigned. A bit of head scratching as to how to turn it but a drawing courtesy of David George indicated that the bearings are externally conical so re-fitting the locking ring and tapping the bearing back using a wood block had it loose so I could rotate it. Fortunately the wedge is still present.
I also realised that the wedges have to be inserted from the inside, and that removing the spindle alone does not allow the pulley cone to be removed from the headstock as it won't clear the casting without also removing the back gear. Fortunately everything is clean and smooth, and none of the thrust bearing balls dropped out, so I decided to leave that alone and simply reinsert the spindle.
I have also dressed out the worst of the abuse on the locking ring slots – mostly it was possible to 'forge' it back into place. They are still a bit ugly but much better than they were.
I will make up a temporary oiler bolt today and get it set up and running. Assuming everything goes well I can then look to make some proper drip oiler bolts and the other short-term need to is to machine a register on a faceplate which I have picked up that has the correct thread but no register, and then probably purchase a backplate for a 4-jaw chuck (having now bought a suitable Burnerd chuck) and do the same.
I might eventually manage to use the lathe to make things other than for the lathe itself – otherwise this could become a self-sustaining project in its own right!
Alec