Although the headlights are working, they are having some issues:

1. there is a constant rumble coming from the headlight adjustment motor, almost like a vibrating transformer unit. It appears to be constantly running!

2. when driving, the headlights regularly drop fully down to re-adjust to normal riding level. I believe this is not normal either, since other xenon-lighted cars I've owned did not behave this way.

The dealer suggests the standard solution: replace the whole headlight unit @1100 euro...

Can you give me some suggestions where to look at, as searching this and many other LR forums did not help me out.

Many thanks in advance.

you will find that there are no transformers in there, I think what you can here is the self levelling/adaptive motors turning, I have had quite a few of these lights apart and the motor is a gear and worm setup, it must be damaged and the noise it the motor turning trying to get it to the correct position and when it fails it must drop and then start again. V8 facelift Range Rover Autobiography 22" wheels.
1976 Harley Davidson Iron Head Sportster

might be better buying a second hand one on ebay  Present :2008 TDV8 HSE
Gone Audi A5 2.7TDI
Gone Discovery 3 HSE
Gone Mercedes CLK
Gone Range Rover 2.5 DSE

where are you, i have a complete adaptive unit from a 2009 car V8 facelift Range Rover Autobiography 22" wheels.
1976 Harley Davidson Iron Head Sportster

Thank you very much for all your replies.

I have a 2003 model (pre-facelift) so I best get a headlight here in Holland.

Is the gear-screw mechanism part of the balast unit?

if its a 2003 then it will be the self levelling unit as they dont have adaptive on that year. V8 facelift Range Rover Autobiography 22" wheels.
1976 Harley Davidson Iron Head Sportster

UPDATE:

I recently received a set of used L322 headlights. I opened one of them and dismantled it to extract the self-leveling stepper motor.

A few days ago, I took the effort of removing the problematic headlight, and opened it as well.
Good to note that the headlight can be removed leaving the wiper on the car!

I replaced the stepper motor by the replacement part. I noted that the stepper motor arm was fully extracted, which left me to think that probably the self-leveling was constantly beating against the extreme, without properly reaching the levelling position. On top of the head unit (when mounted to the car), there are two adjustment screws, which mechanically position the headlight. Both, I turned in an equal 4 rounds, to allow the stepper motor to reach an adjustment position before the end-of-stroke is reached.

I mounted the adapted head unit to the car and found the stepper motor soon to reach the self-leveling position. The previous noise was gone! So apparently it was either a failing stepper motor (which I more and more doubt) or the wrong mechanical setting of the unit.

The left light still re-adjusts itself frequently during drive, but at least we can now use the car without the constant noise.