When I was up at Mike Bainbridge's the other month he had a couple of diffs knocking around (he was trying to educate me by showing me the differences), not sure which specs though try giving him a call.
The car at Malton is mine. No spare diff, I'm afraid. Spares include lots of OZ magnesio wheels (3 sets IIRC) and various other bits (DME, ABS brain, tinwork, original 3.6 rods/cylinders/pistons, a door skin, an oil cooler, a bag tank etc).