They don't fail the mot providing they are aimed correctly and they are the right colour, their fitment is irrelevant.
I Have heard they are cracking down on Hids and whats needed to run them, I lifted this off a MOT tester forum.
Quote:
Vehicles with HID headlamps are therefore required to have a headlamp washing system (a wiper is not required) and be self levelling, which may be achieved either by the use of either headlamp or suspension levelling systems.
The presence and operation of these headlamp cleaning and levelling devices has been added to the test. Therefore, if a mandatory headlamp levelling or cleaning device is missing, inoperative or otherwise obviously defective, the vehicle will fail.
This raises the question of whether these checks apply to vehicles fitted with after-market HID lighting kits. These kits convert conventional halogen headlamps to HID Xenon and they are widely sold and fitted to vehicles used on the road. The Department for Transport considers that after-market systems should be required to meet the same safety standards as that applied in respect of these lamps at vehicle Type Approval. Therefore, in order to pass the MOT test, vehicles fitted with after-market HID systems would also need to be fitted with headlamp cleaning and self-levelling systems. Some high specification estate cars are fitted with a self-levelling suspension system and this would be considered as adequate for the purpose.
It is also worthy of note that a few high performance vehicles fitted with HID headlamps that have barely any luggage space and stiff suspension do not require a self-levelling system.
HID headlamps can be easily recognised as they generally:
u take a few seconds to reach full intensity
u have a bluish tinge to the light
u have an igniter module/inverter behind the headlamp
u may also have ‘DCR’ marked on the headlamp lens.
Headlamp washing and levelling systems are mandatory for all vehicles fitted with LED headlamp systems, although these are not yet widely used and only tend to be optional fitment on some executive marques. However, as LED systems improve and because they can be arranged in almost any design configuration, they are sure to become more common.
Where headlamp levelling or cleaning devices are missing or defective, but there is doubt as to whether they are required, the benefit of the doubt should be given and an advisory notice issued.