are the wires there from the series 3 loom or the engine(im taking tthe engine was a dihatsu, now a 200tdi out of a landy disco or90?)
if its a lucas a167 alternater
thick wire is B+,
this goes to the battery, positive terminal:P
if you have a rev counter, it goes to the W connecter
your diode wire is F, it is the wire that runs off to your battery waning light.