does it show 4th gear in the instrument cluster?
Yes it does.
The car was engaged in reverse when it initially stalled and, when I try to restart it, 4 was shows in the intrument cluster but ,oddly, the reverse light comes on too so it's almost as if it's jammed between the two gears but why 4th I don't know (it obviously can't have been in that gear at the time so I can only assume it's some sort of electrical/ software fault).
Thanks for responding.
check the fuses 60 amp next to the battery.
Fuses 7,14,33,41 &45 these are all for the transmission control module apart from fuse 14 which is for the starter inhibit relay.
Check all the earths attached to the gearbox for security and corrosion these are awkward to see though(they bolt on top of the gearbox).
If all these are ok check the wiring connector at the control module located just in front of the gearbox.
Check the wiring to the two shift motors on the front of the gearbox.
If there is nothing obvious it could well be the control module that has failed.
If you remove the shift motors to put the transmission into neutral manually you still need the motors to be at the neutral position as there are sensors inside the motors to tell the module that the motors have moved to the neutral position.
I take it the transmission warning lamp is lit.