This might be handy
Cheers fella, I have a hard copy of that exact manual at the workshop. I'll do some investigative investigations and investigate

Dont trust the gauge! its 30 plus years old It could be true but have you a Semi calibrated meter that you can bodge on for a test run ??
Remember these old beasts there's a sort of a rule that if the light is on when ignition switched on and it goes out when revving / moving above tickover then there is output from the alternator rect reg assembly ""which" is higher than the battery voltage"
Search gammotronix on E bay its a small voltage sensitive LED and it will speak words of truth (well its a good visual indicator)
That is a very good shout mate, I think I can cobble something together with my multimeter to get a more conclusive reading



