There was one the same as this, or it might have been the extra long wheelbase, in Tennant creek in 1974.
It was initially bought by the govt. to carry Prince Phillip around when he visited N.T. a little earlier.
It was then passed on to the Health Department, which being staffed mostly by non mechanical types, they let it run out of water and cooked the engine but fortuneatly not seizing it.
The guy I was working for had the mechanical contract for government vehicles and it became my job to recondition the engine.
The engine was a 6 cyl Rover petrol engine with overhead inlet valves and side valve exhaust. Somewhat old technology that worked well.
I was able to remove pistons and con rods without removeing the engine from the vehicle. I honed the bores first and then one by one slid out the main bearings, linished the journals and replaced the bearings.
Big ends, rings, valves etc were replaced and as I recall were able to refit the original pistons. When finished it ran as smooth as silk and I thought it was a very well designed piece of machinery.
As you say GD:-
"She is a work horse...a bit of a Clydesdale if you ask me

"