I still cannot think of a reason why everything went at the same time, but I have a few ideas that might help.
Though not marked on the wiring diagram I am sure I have seen a dimmer switch for the dash lights on series 3's which, if fitted, would be a good candidate for dash light failure, otherwise the switch either of which you can bypass to check.
Check your temp gauge by earthing the green blue wire, you can do that under the bonnet by taking it off the temp sensor and clipping it to the metalwork, gauge should head for hot.
As you say the choke light is off I would have the steering column shroud off and check the connections at the back of the fuse box, give them all a good wiggle, especially the link between 5 & 7.
The last thing....as your land rover is ex-mil the wiring could be totally different to the wiring diagram. :undecided: