They harp on about HIDs (of which Xenons are a form of) dazzling due to dirt etc on the lamp, or having passengers the car being laden (boot full).
All of the above situations could very well apply to retrofit Xenons?
The downside of this extra brightness is the potential to cause excessive dazzle to oncoming
traffic. To combat this, HID headlamps often have advanced electronics that control the shape
of the headlamp beam to avoid dazzle when the car climbs or descends hills and likewise when
the vehicle is accelerating or braking.
Dazzle can also be caused if the lamps are dirty or aimed too high due to, for example, carrying
rear seat passengers and/or heavy items in the boot. 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