@Angus242164 Strangely I can't get the AW71 to link up to the gear selector using the actual 240 shifter linkage.
I had a look at the diagrams and found the selector lever on the gearbox is longer than the one I have, so I swapped on the correct one that I pulled from the AW72 I had lying around. This made it worse. The issue is that the shift linkage is too long, even at shortest setting. Below you can see the one I fabricated that works vs the actual one.
I suspect the gear selector box (original, 1981, BW35) needs to be changed for a later one with a longer throw.
Spewing because I had one of those gear selector assemblies and I binned it when moving house.