Vehicles equipped with High Intensity Discharge (HID) or LED dipped beam headlamps may be fitted with headlamp washers and a suspension or headlamp self levelling system.
Where such systems are fitted, they must work; however, it is accepted that it may not be possible to readily determine the functioning of self levelling systems. In such cases, the benefit of the doubt must be given.
This it the same for pretty much anything on an MOT - if it's fitted, it needs to work correctly.
Actually according the EU law (which overrides UK law) they don't. All that is required is that the HIDs are in units E-marked to have them in, for that car (and adjusted correctly, obviously).
As such, no car that didn't have HIDs in as OEM can have them, legally.... unless an aftermarket supplier's gone through the massive rigmarole of E-marking their units, which they won't have.
