I can ask around. A friend of mine does some work with Hewland for custom-designed 4x4 transfer boxes, so the contacts are there.
I'm regarding it as a reasonable price "believed-good" box to keep in the garage in case mine (with 8s) spits the dummy. If it is 8s in there, so much the better. If not, it's not the end of the world. In either case, it'll probably head off to see a mate who rebuilds 2cv gearboxes (very, very well), so he can have a look and see if he fancies adding them to his repertoire.
Where's the thread that gives a list of the various revisions of 'box? I gather this is out of an '88/9 car - so might or might not have the various later improvements.