I'm gonna stick my head out and say, Lucas systems are not worse than any other systems. Looking and 1940s-70s, their untraditional way of using electrics, AC instead of DC and people's lack of understanding electrical flow has had many frustrated. Yes Lucas system is complicated, but not hopeless. Positive earth adds to the confusion.
I'm fascinated that they where one of the pioneers of alternators, three wave AC chargers and semiconductors usage in vehicles. All modern car generators use this setup today.
Their Zener diodes was a smart weight reduction (crude) method. (Crude like people using resistors as 12-6v reducer ?)
Lucas's series wound generators differed from US and German shunt generators. These also has different regulators.
I'm gonna stop now, I think I'm already in a line of fire LOL