Surplus to requirements is a Gertrag 5 speed manual 'box plus all the relevant parts to convert a 4 speed to a 5 speed. This only fits the M102 4 cylinder petrol engine though, not the diesel.
Included are the following parts designed to be used with the 5 speed 'box:
two piece propshaft
Gearbox support
Correct speedo drive cable
Gear lever with mounting and rods
Brand new clutch assembly
It's on eBay at the moment:
Collection only from Milton Keynes.