I finished the job yesterday and my bike starts like NEW! I cleaned out and replaced the O-ring in the drain valve too.
Still need to bleed the brakes/clutch and she should be all ready for a season's riding.
Anyway, my starter clutch was pretty bad... but not terrible; The three bolts had worked loose and were damaged, and this caused the whole housing to rotate slightly etc. But all the pins and springs were still in place. Idler gear was prestine.
I think the slow starter was 80% of the problem. I'm glad I have a new starter clutch, but it wasn't nearly as bad as I expected to find it. It would make a horrible "clatchy-cracky" sound often.
thanx again for the advice.
Chris