Starting problem

ive had that too pal..... mine was the clutch lever.... had it adjusted too far, a little tweak or even one notch made it ok.
Hope yours is as simple as mine
have you been playing with your lever

 

Clearly the battery (though that could be due to the rectifier)... ain't gonna start with less then 12v (mine takes 12.6v to crank!) Ain't any of the switches or it wouldn't even turn to begin with.
My battery went in February, it would charge upto 14v+ and sit at 13v+ when unplugged but as soon as I hit the starter it would drop to 11.7v and instantly kill the battery.... changed it and all good again.

 

I seem to remember reading somewhere that the ECU will disable starting if battery voltage drops too low, think it's there to prevent damage to the starter/sprag clutch (but I could be talking bollocks).
Anyway, if you've got a car battery and jump leads to hand I'd give that a try, if it starts ok I think it's safe to assume it's new battery time. (your voltage readings don't look great)

 

Somewhere on this forum is the same problem I think it was a main wire from the battery into a terminal which had corroded hth

 

There is a system of protecting the ECU by preventing electrical load when the battery is under a certain threshold
It would be worth having both the rectifier and stator checked, as a damaged rectifier can easily lead to a damaged stator