Thanks guy's, I have light and sound.
I put my test screwdriver on the headlight switch and no power at all going to that. So remembering about what you said about the purple wire for the horn I started tracing and didn't have to go far when I found I had no power going to the drivers side fuse in the box. So I ripped all the 40 year old tape off my wiring lume to trace the brown power wire which feeds into this side of the box and then found 1 of the 5 power brown power wires coming from the starter solenoid had come free from the terminal connector.
Thanks Brad