I've got a new layshaft bush for a s/a, the blind one on the drive side, I could not use it as I needed and undersize one made, I'll measure it and let know the results, of course one can't be sure the supplier has got the dimensions right and you will need to check the part is the same on your box.
Out if interest what is the gear bearing face that wears against this bush like on your box? Smooth or with splines on the inside like mine?