The procedure described in the thread below improved the gearchange so much that I thought I do the same on the X250-based van that I've just bought.

https://www.fiatforum.com/ducato/296026-ducato-2006-clutch-gearbox-issues.html

Unfortunately it's made it worse and I know I shouldn't have fixed it if it wasn't broke

It seems that there is not a shoulder on the pivot shaft for the washer and securing nut to bear up against as there was on the 244 and so tightening the nut fully has tightened up the pivot!

Loosening the nut slightly restores the free horizontal movement of the gearlever back to what it should be, but this goes against all my instincts albeit that the securing nut is of the self-locking variety so shouldn't come undone

Just wondering if I've dropped a spacer or something in the driveway or whether this is just how it is....

After some tinkering with this I think I've sorted it.

The pivot operates the gearbox shaft by means of a steel nipple fitting into what is termed a 'pad' on eper, basically a semi-circular plastic moulding with a dimple for the nipple to locate in.

I wasn't locating the nipple properly into the dimple (which I only realised when the pad came out of it's housing and fell on the floor) hence the pivot wouldn't go fully home on the shaft.

With everything correctly assembled a shoulder magically appeared on the pivot shaft to tighten up onto.

In future I will lubricate this shaft by dribbling some thin oil onto it from the engine compartment!