Hi Darren,
I don't know about 'normal' Landies, our has a Ford 3L V6 conversion, we've got the earth going to the engine, bolted on at one of the alternator bolts, then also on the same bolt is another rather long lead running back past the battery, and bolted on the the front panel at the top to the left of the radiator. Our battery in the engine bay btw - Series IIa. I can't see another earth to the chassis, but it's in the garage, and I store stuff underneath so can't go crawling.
If I remember, I'll have another look tomorrow night - out for pub meet.
As for your battery / alternator. Beg, steal, borrow (or maybe buy) a multi-meter, they are a proper useful tool. As stated above, with the engine on, the battery would read 13 to 14 volts across, then with the engine off, ours certainly settles at 12.68 volts, where it stays. Ours used to lose voltage with the ignition off, it had been connected up wrong on the positive side when the conversion was done, I have since corrected this and it doesn't lose anything now.
I don't know about your starter motors, not got experience of that yet.