It was quicker to run a new cable than figure out what Morgan did. The electrical practices of MMC are terrible. I worked for several NASA contracted aerospace companies when I was younger and I know good wiring practices when I see them.
You have to be a bit of a detective Stephen given the wiring schematics provided, although all the clues are there. The reverse light wiring is in place to cover the Australian versions which require such ex factory. Once found the colour codes follow normal practice used throughout the car industry.
