N.B. the operator’s manual was for the 4X2 model and in Chinese!!
Moreover, some sections not visible from outside the vehicle were not painted at all, not even with primer: bare metal left exposed.
This problem has been tentatively identified as being cause by too much play in the whole system of linkages and rods from the gear shift lever to the transmission. I have disassembled two pivot points, drilled and tapped to install grease zerks.
I will update on this as we try to optimise the situation, naturally without any help from Chengli.