[Adrian E]

The changing requirements for MOT result from changes to minimum standards for EU Directives regarding roadworthiness inspection

The requirement for factory fit systems is that if fitted with self levelling and washers at manufacture they should function and not produce a fault code.

Where it's less clear is whether just having HID bulbs fitted in filament compatible headlights will mean an automatic fail without levelling/wash or not, if the beam pattern isn't too horrific (most are)

The AA cover it in simple form:
http://www.theaa.com/motoring_advice...nges-2012.html

C&U regs haven't been updated in over 20 years, bar a few minor amendments, and for construction purposes are now entirely redundant as any ECWVTA approved vehicle must be accepted for use in the UK under the Vienna Convention in any case. For use, they're the lowest standard a vehicle that can be used on UK roads must meet. Obviously there is then an enforcement issue and for the most part we've not had substantial change to the annual test since the introduction of emissions testing until this year. Generally you were OK to do what you like unless the catch-all section of C&U about causing danger to other road users could be applied - it was a pretty wide definition!