For anyone interested, I guess it's been a while since I posted an update.
Grover has been very reliable. To date, I've only had one 'failed to proceed' incident, but that was only at the end of my street, about 50m from home. A transmission hose ruptured, dumping all the fluid onto the road, leaving me with a gearbox full of neutrals.
Average fuel consumption seems to be around 8.5L/100km. I've had trips around 12L/100km towing a car trailer around town, and I'm happy even with that. Best I've seen was on a run to Traralgon and back, average was 6.8L/100km.
Being a 'prototype' kind of project, it will never be finished. Recent work includes the fitment of a much larger heat exchanger for the intercooler fluid. It's enormous compared to the old one, and when previously the coolant line into the intercooler itself would get hot after some mild work, it now stays at ambient in all conditions I've been able to throw at it.
Intercooler liquid heat exchanger fitment between radiator and AC condensor:
I have also recommissioned the cruise control, so that has made long trips much more pleasant. As is common with many modern low-revving diesels, it's difficult to hear a change in engine speed on the highway, so you quite often look down and suddenly see that you are travelling much faster than anticipated. Having cruise has solved this.
The next project I'm going to tackle is to improve the airflow through the radiator at low speeds. At anything above 80km/h, the engine temperature is very steady, regardless of load and conditions. But below that speed, if towing a heavy load up a long incline, or if climbing at 4WDing speeds, the temperature tends to climb.
At the moment it only has a 16" Davies-Craig fan on the back of the radiator, and the AC condensor fans on the front. My plan is to replace the rear D-C fan with a fan from the original 406, shrouded to cover about 2/3 of the Range Rover radiator. Hopefully this will keep temps under control. If that still doesn't succeed, I'll be putting an engine-driven viscous-coupled fan on the front of the Peugeot engine.
The last project to tackle will be air conditioning. It's something I've not worried about to now, but as we are using this car more and more and starting to travel further afield, it is becoming a requirement. My two options at the moment are to use a 12v marine type AC compressor, or to change the power steering over to an electric pump and fit the engine-driven AC compressor in place of the original power steering pump. At the moment, I'm leaning towards the latter.