Oh boy... Nigel, there is a return line, going from the basepan to the alternator. Its only short, about 3 or 4 inches, and then there's another line, on a banjo fitting, going from the alternator to a spot on the block, inboard from the oil filter.

IF your leak is from underneath, I'd be checking that lower one first. Not a proprietary line or anything - just measure inside diameter, and get a line that's oil-safe. Replace those silly squeeze clamps with actual hose clamps and you're good to go. That would be an easy fix bud. Let's hope for that one.

As far as the seals, mine wasn't showing any oil leakage outside the alternator, other than an accumulation which wasn't really obvious - certainly not gushing out like your Exon Pajero Valdez. The shop did my seals between the pump and alternator when they did the rebuild.