With some advice from the folks on the LTD forum, I gave the top of the stem a sharp rap with a hammer and piece of wood and the stem dropped out, leaving the upper bearing behind, which then lifted out. Both races show some pitting, which looks bad but I can only just feel them with a finger tip. However, the Haynes manual says:
If even the slightest amount of wear or damage is evident, the races should be replaced with new ones
Bearings seem to be readily available for non-crazy money, but I’m struggling to locate races. More questions!
Update: found a full set of bearings, seals and races…in the US. Think I shall be taking advantage of my executive courier in August 🙂
Further progress, removed the centre stand with a lot of heat and wrestling. Something peculiar had been done to it on one side. If I want to re-use it, it will need a lot of cleaning up, possibly welding. Also removed the helmet locks and side stand switch, which all had to be drilled out. I just need to drift out the races and double-check for any remaining bushes etc to be able to start cleaning it up for painting/coating. It’s been suggested I get a bunch of bolts and thread them in wherever there are thread in the frame, to keep out the grit and powder to avoid having to clean them out. Makes sense.