So, a couple of attempts later, I think this will do.
Routed the wire behind the plate like this to start with, but the flywheel was rubbing slightly, so I decided to try a different path.
Also noticed that the attachment of the red wire to the coil looked pretty sketchy so I got the soldering iron onto it and put a new wire on. Hopefully this doesn't mess anything up.
Have got a spark from lead to head once, with a few attempts, but couldn't get anything with the (new) spark plug grounded to the head.
Will reassemble further over the weekend hopefully.
