Not meaning any disrepect but I can now see why you had issues in the snow (but then other people may have had issues too).
I think you need to sit down and read your handbook and if you do not have one download it from the stickie at the top of the L320 section. (oops not there as yet but is here https://www.rangerovers.net/forum/9...6-2005-2009-owners-handbook-repair-guide.html
Yes the knob is the Terrain Response selector and by choosing the correct setting for your situation and knowing how this works it may have helped you. A tip is as mentioned - whenever offroad turn DSC off (the switch marked DSC at the top of the centre console above the radio) - Direction Stability Control (DSC) is designed to help correct skids and is normally on. When on loose surfaces it can cut in and cut power and apply brakes as required so hindering efforts to get out of sticky situations. Be warned though and changes in TR and DSC switches back on so you need to check it. Onroad just leave on as if may save your life in a high speed sideways skid.
You said "Well, here’s another issue then. The fluid reservoir on passenger’s side of the radiator that is responsible for sideways leveling, I believe, has been removed. That would affect the dial control modes wouldn’t it? Maybe the dial doesn’t even work with that reservoir removed?? "
I am not sure what you are alluding to here - someone mentioned ACE but I do not have ACE on my car so I am not sure what components live in the engine bay. ACE
is a hydraulic assist system that works with your anti-sway bars to help keep your vehicle level on hard corners.
So really will have minimal or no impact on TR settings - ACE is useful for onroad handling but will have no real impact when stuck in snow - it will not level the car sideways in that circumstance. As i said I dont have it and I dont need it but then I have the lowest powered RRS there is with a 2.7 litre diesel.
So go through the handbook that I have linked above so that you learn the complete functionality of your vehicle.
Good luck with it.