So I came in to my driveway yesterday hit a bit of a pot hole and when I stopped the range the front right corner was deflating, there was a loud hiss and it went all the way down to the bump stop, thought that was it I had done a shock in so started it to move the car, it re-inflated as expected and i parked up, came out in the morning and it was sitting up perfectly, drove for a while - fine but then after a few speedier corners the front right was down again, i sat it up in extended height mode and it sits up fine, cant see any leaks, but if I put it in access mode the front right is lower than the others , cant hear any leaks, suts fine overnight even in extended height, no fault codes, level sensors responding correctly by the 4x4 info screen,

Is it the airbag or a valve block or what ? Current Vehicles :
L322 2010MY TDV8 Autobiography
BMW E38 735i
BMW E63 645ci

Physically check your height sensor/s are intact and in place

Put in off road mode, then lift the corner manually (your back to wing, hands on wheelarch, legs do the lifting) - listen for any hissing - leaky bag

Probability: leaky bag... .
Experience is the only genuine knowledge, but as time passes, I have forgotten more than I can remember
Volvo V70 P2 2006 2.4 Petrol 170bhp Estate SE
MG Midget Mk1 1962

Previous: L322 Range Rover TDV8 3.6 2008; L322 Range Rover TD6 3.0 2002; P38A Range Rover V8 1999

I had much the same, did the wheel arch lift no hiss, stayed in off road over night no problem if I remembered to raise it. In normal height it sank front nearside.
After a couple of weeks denial it sank to bump stops at the front. Yes it was a leak.
Due to weather and ill health I let Cam Tech sort it out for me.