An Update on the thread,
I could not find any source of a seal but found that the seal could be moved into the end cover a millimeter or two moving the lip to 'new', unworn part of the shaft to improve sealing. The end load from the rotor is taken by the spider and shims onto the end cover.
Subsequently I found a 'service' listed on one of the Japanese supplier's web site but they had noted it as No Longer Available!
I have now found the similar kit on the Honda Classic's web site, ordered one and delivered today. Said to be suitable for several Honda models and includes bearing bushes, seal, O Rings, Brushes, Brush Springs etc. Web site listed as 2 in stock and I have taken one. So if anyone needs a kit there should be one left, ref KIT114.
Pic attached.
