OK, continuing . Transfer case Module was replaced. After tinkering seems to have got past (temporarily) VIN issues and or programming. Playing around with adaptions, etc. I fluffed my way through and the moor is running well. But after playing further/disconnecting battery. I had upset programming and reverts to previous fault.
But again I was able to get the car running well again by tinkering in the diagnostics. So this has been a big learning curve for me and was still a lot well above my skills.
To those who know. What is involved in programming the VIN into a new Transfer Control Module? I have a basic OBD Analyzer, but apparently is has some (limited) programming ability (poor to no documentation). Any advise please.

Been quite some time, with too many issues at hand. But now back to the Range Rover.

After all this and probably more, that I want to forget. Most recent state of the Range Rover is a little smokey, no power, not even enough to move on a flat surface (unless down hill). Poor Idle, Fuel Trim was all over the place but default to 1000 and wont vary. Fault with injector 4 has cleared, but now a fault with injector 6 (all injectors replaced previously) --Injection timing on #6. What is going on??

When the EGR was physically removed. Seemingly there was no consequence to the operation of the car (though I was dealing with some misdiagnosed faults). Latter an error on the dash would appear for the EGR. OBD would clear that but it would come back. Internet searches and advice from Diesel Mechanics, told me not to worry about it this will not effect the running of the car in any real way. When I re plugged EGR back in, Electrically only. It made no difference. The Running got worse. Smoke, Poor Idle, and eventually not revving beyond 2K, etc. The EGR fault would not clear anymore and symptoms were getting worse. I was considering scrapping the car (That is after paying $25K plus hate to thing a further $5K to $9K in parts. Reco Injectors, Injector Lines. Main ECU & program. Misdiagnosed HP Fuel Pump, thank you Land Rover Dealer).

Today,got some good weather, Back was not causing much pain and I was able to get back t it. In the back of my mind the EGR was always niggling at me. So I bought some resistors and made a passive EGR Emulator. Plugged it in and presto. The Running was improved. I was able to Rev the car. Cleared the fault codes and they disappeared, Engine fault codes are gone and have not come back. Reconfigured 1 of these emulators as I miss-wired it (causing smoke)engine saw electrically wise, 1 EGR open, 1 EGR closed. Smoke all gone and car is derivable. I am still working on it. But no smoke at all, Idling a little rough but otherwise idling properly. Engine seems all good.

Now I'm happy that I can see the light at the end of the tunnel is very, very close. The car is driving and my summation of the situation is; Electrically most people have no idea in the complexity of these cars (even Land Rover Tech's themselves). Seems that disconnecting the EGR will cause issues, no matter the online research saying otherwise. It may be possible my model is one in-between an earlier and a more involved EGR perimeter of operation (Who knows?). It seems the car will be happy with EGR problems for a short term. It may or may-not throw errors immediately. But give time will most likely. Also the same is true of the running of the car. With time the car will run bad, Smoke and eventually not rev. In other words go into a very bad state of Limp Home Mode (but there wont be enough power to limp Home). As soon as I fitted my emulators (as I stated static Emulators. Meaning there is no running adjustment). They are a fixed value. The car is now happy, Clering Fault codes now possible and improved running.

In a nutshell these cars do need EGR and if removed will have problems. These issues may not be immediate but they will appear. I expect that different years and locality of these cars may cause different symptoms or severity. So the only solution is to keep your EGR, Replace your EGR or have it repaired. Other that that 9dependant on ise and local laws have EGR Emulators fitted or better, have the EGR removed at a software level. I expect there is also a Fueling change required. As with these Static Emulators. at low Rev's and particularly when motor is not warms. These is some detonation.

My EGR Valves, have been disassembled by me. Mechanically they are great but electrically they are not. These are an electric motor that drives some gears. In turn opening/closing a valve. On one of the gears this valve has a feed back loop. That senses the valves position with a wiper arm om a POT or VARIABLE RESISTOR. This wiper arm was Broken or Worn? I am surmising it was intermittent and causing my running issues that lead into all this drama.

Admirable commitment Davidno64!

Congratulations on solving your problem and sharing with us.

Strong hug!