Ohh that was a blonde moment.
Oh course you can just take off the whole footrest frame assembly.
So anyhow, clutch taken apart. Three broken friction plates, the three outer ones.
Close examinaton reveals a partially missing tang from the clutch basket and a slightly bent one (inwards)
Friction plates were difficult to get off on the last few millimetres so I carefully filed a couple of the basket "fingers" and a mil off the bent tang. This allowed the plates to actually slide and not to bind.
I 've put everything back together now, but I would appreciated some advice about aligning the kickstart return spring so it has tension as I put the cover back on.
cheers Neil