Went back to Google to see all of this thread, as I used to own a "1973" FFR that has some similarities to this vehicle. No evidence of it being a fire engine (beyond my own extinguisher just in case), and it isn't the same vehicle.
It had the generator panel where you describe it. In my experience the generator and shunt panels could be in a variety of places. The rear bulkhead was the most common - but it could have been either side. I also had a new rear chassis section - it seems common in the military 109s that they were used for more towing than they should have.
And just to stir thing up, Beverley said it was a 1973 vehicle, but it was tax free. (alas the MOT wasn't!!! lol)
'L' Reg. Beverley listed it as being delivered to Ashchurch on 17th January 1973. Land Rover product records show it coming off the production line on
30th or 31st August 1972 (can't remember exactly which, my copies of the paperwork are filed away). A fluke, but a good one :-)
Gaydon provided the necessary letter for the tax-free registration, but the letter had nothing of any real interest on it.
Richard (M)
Richard Marsden Winwaed Software Technology
formatting link