Firstly I would like to thank you all for the feedback - you really are providing insight I cannot get elsewhere.
I have changed the battery for a new one and have 12.55 after leaving the hood open for a while. When running it shows 14.8 but I need to recheck since I am unsure if my meter is correct.
I plugged in the IID Tool and used to get the alternator reading on the dash but don't anymore - odd.
Off for a test drive!

Now, CAN.
The way the bus seems to work is that each member can send a message and neither expects nor checks for a reply. Any other member can pick it up and do what it likes. A receiving member can get nothing and never know why.
So, how does a message like 'U0101-00 (68) Lost communication with transmission control module' make sense? It is not communicating from A to B but just transmitting. I can only think that, like Ethernet, it can detect that it can't send so it assumes it has lost communication. Not being able to send can be as simple as low voltage on the bus.

 

So, no signs of any problems but this doesn't mean there is no problem.
Using a more accurate meter, the battery is 12.4v in the car and is only two days old so it should be OK. Running is still 14.7
I suppose I will have to drive it until it breaks down again..unless anyone has other suggestions;?

 

If the battery voltage doesn’t come up to about 12.6-12.8v after sitting a while (maybe even lock the car), you might have some kind of parasitic drain. This also can point to a bad alternator (diode goes bad and pulls juice off the battery). One thing you can try is testing the voltage of the disconnected battery (after driving for a while so it should be at full charge). If the battery comes up to 12.6-12.8v when disconnected, but not when connected, there is some kind of excess drain going on. You’ll always have some drain, but I think it should be no more than about 30-50 mV as I recall.

If you do have a parasitic drain, you can start looking for the source. You can try disconnecting the alternator - see if that brings the voltage back up, and you can test the fuses for voltage using a multimeter on the test points to try to track down the culprit. Time consuming process though (there are lots of fuses) and you need to keep the key in the house or the car can start turning on systems and through off your whole investigation.

I would still encourage you to check the earth strap as well - see if that connection point to the fender is corroded. I’ve seen this reported in various forums over the years mimicking alternator problems, so it seems to be an issue with these cars: e.g., https://www.aulro.com/afvb/l319-disc...rth-strap.html. The corrosion can cause an intermittent disconnect from ground. I think you probably need to pull the wheel well splash guard to see it. If part of the strap is exposed in the battery compartment, you can also touch it with your hand after driving for a while - see if its warm (which would indicate higher than normal resistance).

 

So far, so good. New battery and no lights and the battery shows 12.6v.
Digging around in the ODB material I cam across an interesting snippet or two. Firstly most people reckon a UO001 code (bus failure) is pretty easy to diagnose and usually due to a duff battery although it escapes me why the car does not seem to have an ECU to monitor the battery and tell me when it is on the way out. My car doesn't have one to my knowledge.
Secondly, the Check Engine light does not mean stop instantly or everyone will die (which is what any garages would have you believe) - it is OK to keep driving and is due to emissions and problems related to that and nothing else.
So, as I said, so far so good and thanks for all teh advice

 

An engine MIL can be an indication of a severe fault so it's best to read the codes and then decide just how serious it is. These are fitted with BMS which is an overly complex battery charging and monitoring system. Problem is it doesn't seem it pick up on faulty batteries and alternators until it already too obvious to the driver.

 

So, after a fair bit of driving with the new battery, the problems seem to have gone. Bear in mind that the battery was perfect from a user point of view - it started instantly even when freezing so who in FR thought a battery with even a slight drop in voltage would lead to these problems to the point of immobilising the car for no reason??

 

Err....no. This morning it all started again at around 100kmph on the highway with the HCD/ABS/DSC/EBD and so on including general system error and gearbox fault etc etc and then, the suspension lowered!

Normally the suspension does not change at speed but someone, somewhere inside Land Rover decided this is OK. This is done by software designed, written, tested and deployed by LR yet it implements something dangerous.Why they have never been sued or the people sacked is a mystery.
I have a garage appointment but they clearly have no clue why and couldn't even tell me what thy will do. I will go but have decided I would rather take the car to the scrapyard than mess around any longer.
LR are overrated, overpriced, over engineered and their service is appalling