Hello, I have drawn the T3 wiring diagram in colour and can supply you with one see here
I do charge to cover my costs, the cheapest is a pdf copy, but the best for the workshop is a laminated A3 copy. You can download Carl Allison’s wiring diagram for free via thisoldtractor website but beware sometimes the colours are not 100% accurate.
I also have hand drawn each electrical component on my bike (originally a 1974 850T now a cafe racer) showing which colour wire connects to which terminal and where it leads to. This probably won’t help you as I have customised the loom to suit changes I have made, but the ignition, lights and charging system are all similar.
Let me know if you would like any help. Where in the country are you?
Best wishes Chris