the earlier 1.0 k11 gearbox's will fit but a little work is required to the gear selector on the car, but no big deal to do, i would have thought the gearbox parts are becoming scarce now, but i wouyld have thought you would be able to get them still,
the very early k11 gearbox's were k10 derived so are probably very similar inside, so that may open up parts for you???