Triumph TR4A Wiring Loom/Harness
The old loom had various issues. So, with a complete rebuild you might as well place the wiring loom. Fortunately, these are available off the shelf purpose built. I reckon it will take a day to fit properly.
The bellow picture should help with the wiring of the ignition switch. It is not one of mine but it did come in very handy:-) Now here for you.