I should have discussed this in my original post above! The original 75/90/GTV transaxle is too long, and the driveshafts are at the wrong end of the gearbox:
I need a transaxle with the output driveshafts located between the gearbox and the
the input shaft/clutch housing.
Having searched the net for a couple of days on this topic, the Audi 016 unit seems to be the most favourable for my application, but it would be nice to know if anyone else has done the same before I start scrounging around wrecking yards...
~Benjamin