Quick one - why does the 2010+ headlights have a halogen bulb if they have the ability to open the xenon flap at the top? When is the halogen used? Current stable:
2006 BMW M6
2007 4.2 V8 S/C FF
Gone:
2002 4.4 V8 FF

It's to comply with construction & use regs. the Xenon would not meet the required light output fast enough to pass whatever the test is for a high beam flash during daylight - i.e. Xenons not already illuminated, they will also provide additional high-beam fill in lighting at a longer range due to the reflector design, whereas the Xenon light is a projector type.

I suspect the fill-ins go back to purely halogen days when the 2nd high beam light made a difference and LR stuck with the twin headlight look until finally ditched with the L405. At least in the D4 but I suspect the L322 too, only the bi-xenons have CE certification in their own right without the fill-ins which have no CE certification and therefore no Australian Design Rule requirement, which I discovered when attempting via Australian authorities to have LR correct the D4 possum-spotter fill-in lights.

The legislation is a minefield, most manufacturers tend to 'broad brush' so as to cover as many markets as possible with one design (NA & Nordic requirements are generally addressed in software) Confusingly the CE markings do not confer the same as the 'E' markings, Harmonisation across markets leads to particularly woolly national legislation such as The Road Vehicles Lighting Regulations 1989, even the UN want to have a dog in this fight with the UNECE scheme, the UK VCA even has a separate UK(NI) type approval, presumably a halfway-house between UK and EU approvals.

JLR are not the only manufacturers to use Halogen as primary high beam lamps in situations where HiD lamps are used for dip/high beam lighting, it's a long time since I was involved with construction & use type stuff but I do remember the requirement for 'immediate on' being relevant to daytime high beam usage, a bit like why there is/was some arcane reason for rear fog lights being tungsten lamps, even though LED's were used for the rest of the assembly...

My mistake in referring to CE markings instead of E markings. It was a while ago and the memory's not so tight.