G'day Bondy and Mark,
That bunch of wires next to the filler? There should be two wires in that bundle. One is the alternator output wire and one may be a magneto kill- I'd have to check. The one with the fuse is the alternator wire the previous owner had going to the battery for charge.
You also show a fuzzy photo of a green wire and a red wire. If they are coming out of a little one inch square black cube (which I guess is the rectifier) then the red one is the alternator output I think, and should be the same wire with the fuse holder on it.
Not sure what you mean by a wire from this bundle going to the solenoid.
Given that the Honda solenoid is stuffed, I'd be putting the old greenfield solenoid back on and using it. That's what Mark meant by plan B

I apologise for mucking you around on this one. The suggestion to use the Honda one was based on the assumption it was shiny and new.
Mark, do those switch numbers mean anything to you?