I ran into a guy in November on vacation here in the states from Kenya where his job is to maintain a small fleet (6-10) of LandCruisers and Landrovers for a charity operating in the bush. When he started a decade ago he just swung wrenches, and now he's in charge of all aspects.
He told me there is no comparison whatsoever in bush reliability between the 80 series and the LRs. Yep, the simplicity of the diesels lack of computers, etc means the engine SHOULD run almost no matter what. But the reality is the LRs are constantly down for a myriad of reasons that are so widespread and random that he cannot even establish a good spares policy for them. One will lose its pinion gear, another will mysteriously destroy a main bearing in the middle of its oil change cycle while full of oil and with a good filter, etc, etc.
As a result, years ago they began the switch completely over to the 80s and it has been a good one. He knows all about every shortcoming of the 80 design and what needs to be done to each one because they're consistent, not random. For instance, he repacks the front axles often and never has a problem with the birfs. His spares kit is easy to predict and he's never caught by surprise when something odd fails because it doesn't happen that way on the Toyotas.
To me, that kind of operational behavior showcases the LandCruiser design and quality in spades and it is not something we occasional users may ever realize.
The Rovers are all parked and have been for some time and their only value is as parts from other guys like him who are managing small fleets of bush-only vehicles who call him from time to time looking for a radiator here, an axle there, a wiper motor there, etc.
So, a bit of feedback from a guy who used both the Rover and the 80 side by side in bush conditions and is responsible for keeping them going. Different conditions than your wet stuff, but I think speaks to the durability issue.
