Well I've given up for tonight, working on the roadside via headtorch got irritating. The rear subframe (steel) gave me multiple electrical shocks with the engine running and revving at about 5k so I guess tomorrow I'm tearing through the electrics.

Dan - I think there were a couple of coils in the parts from you. I've since got hold of a few more of unknown condition. All tested ok a while back on the table but may be duff under load. All the HT leads are recent (yours). The loom as you must have seen is mind boggling, I think prior owners tried to wire up their house to the bike or something, the amount of added bits and connections that just don't make sense are baffling. I've almost finished rebuilding the spare loom for the project, though it still needs heatshrinking and a few new connectors.