Hi Keith,
Hopefully you will have this sorted by now, if not here goes :-
1/ The tailgate lock is interlocked to central locking and door glass. Unlock all doors with fob, turn on ignition, lower rear window glass fully. (If door glass won't open, it's not the handle at fault) Turn off ignition, try door handle. If no luck -
2/ Un-code the radio (if applicable) and disconnect the battery for 5 mins. Reconnect battery and try 1/ again.
3/ Failing the above, get physical. Haynes (or equivalent?) manual is almost essential, unless you're a good bodger.
Open LH back door, fold both rear seats, remove luggage cover roll. Equip yourself with a torch, mirror and 1/4" ratchet set fitted with large crosshead bit and possibly a universal joint. There are 4 off cross head screws under the door pocket, at about 45 degree angle. Unscrew these, possibly involving trimming a bit off the pocket skirt. Heave on the pocket and the panel should pop off across the bottom and pivot up (I haven't tried this with the tailgate closed but it looks workable). Unhook the top edge of the panel and retreat. If you've got this far, disconnect the battery (as in 2/ above) to ensure that the window glass won't drop on your fingers. Peel back or slit the waterproof membrane (handle corner only), this will expose the handle nuts and wiring. If you unbolt the handle it should fall off and you can tackle the wiring from outside. There should be two pairs of wires - one set to the microswitch and one set to the lock barrel. Reconnect the battery, stand behind the car, short the 2 microswitch wires together, the window should drop & the door catch open. I don't know if the microswitch is standard industrial type (buy from Maplin, Amazon, etc.,) or LR proprietary. Reassembly can be done with the door open (much easier), using gaffer tape, clear silicone sealant etc., to keep the rain out.
If the microswitch is not faulty you are in the right place to work on the window glass mechanism or drive the door lock motor open electrically. There should be, again, two pairs of wires to the lock motor, disconnect both pairs before trying anything to prevent possible expensive damage to the control module. The door physically won't open with the glass fully raised, there is a relay (helpfully buried under the RH rear boot side trim panel) which drives the glass up and down by reversing the motor supply. If you know what you're doing you can disconnect the wiring to the motor and drive it directly. If all else fails, I guess dismantle the raise/lower drive mechanism until the glass drops.
Regards, Bryan Stark
