I lost the adjustment of mine when I fitted the Hitchcock's outer gearbox cover stiffener kit (which does save a bit of lost clutch lift and sweeten up the gear change). The kit uses the mounting hole for the eccentrically drilled stop bushing that the neutral finder bears against. Of course, I should have marked the orientation of the eccentric bush when I dismantled the outer cover...
However, I reinstalled the bush to what looked about right but I didn't have enough bush wall under the neutral finder so it was pushing through all the way to first gear. Then, I rotated the bush so that it held the neutral finder lever a bit higher. This time, the lever couldn't drop enough to let go of second gear. I then set it to somewhere in between and it now works properly.
The adjustment seems quite critical so I will mark the position of the bush - the extra cover stud of the stiffener kit means that the bush has to be disturbed every time the outer cover is removed.
Other posters could maybe advise if there any other adjustments to make under the outer cover.