After checking obvious like battery terminations and earth strap cable. Check wiring at the ignition switch - the spade connections there are not good at best of times, might need a wee wriggle to bring back to life. (Recently had this with an old 110). You get at ignition switch terminations by undo the instrument panel/pod fixings, reach behind and disconnect speedo cable, turn the panel on it side and you can reach down and get at the wiring behind the barrel switch.
Hot wiring >> add a perm live wire to the fuel stop solenoid (it's on the injection pump) and use something heavy gauge to short across the starter motor solenoid to spin it over. Disconnect the fuel stop solenoid wiring to turn off engine.
Time like this where RAC/AA recovery to home membership pays for itself, I suggest to get covered in future especially with a landrover.