In terms of bolt spacings, any honda with comstar wheels will have the same pattern, so superdreams, cx500 and even cb650/750/900. Whether the diameter and offset suit I can't say, but I know comstar wheels disks fit an rs hub cos I've done it albeit years. Ago.

That plug looks awful, so a new one should improve matters. But it does beg the question how did it get like that? Looks like oil fouling to me, implying valve guide / piston ring issues.

Thanks Ian
Basically I think it may be the original plug! It's certainly the one that was in the engine at 59,000 miles. I was always sure it would break off like others had if I tried to get it out so left it while the bike was still running which turned out to be 60,000 miles later. I'm pretty sure the bore will be well outside spec at nearly 120,000 miles and it does use a small amount of oil.

That plug looks awful, so a new one should improve matters. But it does beg the question how did it get like that? Looks like oil fouling to me, implying valve guide / piston ring issues.

Try and add piccy again
https://photos.app.goo.gl/G9eFJ2rDjwdj8RL6A
[https://photos.app.goo.gl/G9eFJ2rDjwdj8RL6A]

It's refreshing to hear some good news Michael.
I'm with you on the dry weather. I've been trying to get out into the countryside on my bikes as much as possible even though on some days it has been a bit on the hot side. I do find as I age I'm less tolerant and extremes of weather are no exception.
Some of you may have seen on the media the fires which have been devastating parts of my home town of Stourbridge. I only live less than a mile from where the fires have been burning so am very  grateful so far to have been spared from these totally random and but incredibly destructive events which have impacted on others . At least our community seems to be rallying round to help those affected and to thank the emergency services and locals who have put others before themselves in taking action to mitigate the effect of the fires.