Going by the evidence I would suggest it's a sensor issue, possibly the wrong one or faulty.

If it reads completely the opposite to the other sensors when they are all being adjusted in the same direction on the IID tool it suggests the variable resistor is opposite to what it should be in the new sensor. That can only mean the sensor is reversed and looking at the figures which are high when all the others are reading low also suggests it's reversed.

Other than that it could be the new sensor is just plain faulty.

Wasn't a Britpart replacement by chance, there is a reason why they got their deserved nickname.

This gives some more info, Britpart replacement never worked properly out of the box:

https://www.fullfatrr.com/forum/post383971.html

somewhere in the manual is written that the lpg should be off, so running on petrol before you can recalibrate. I remember it is written in red.

Evening Chaps,
I thought I'd update,
the new height sensor was removed and the arms swapped over. The fatty was sitting right within 20mins!! And has behaved well so far.
so thats another strike against the Britpart sensor, so I'm never using britpart sensors again.

I want to say thanks to all of you taking the time to help me and the many others on the forum.

jake 2003 Range Rover Vogue 4.4 on Gas
1961 88" 2.25 diesel - George
Gone - 1997 3.9 V8i Discovery - Burt