I suppose from time to time we all state as fact things we only befieve
to be true. I plead guilty.
I stand by what I said about it being a requirement of the construction and use regs (or their e.u. equivalent), and know for a fact that it is a requirement of the SVA test (if you build a kit car), but no, I cannot say that it is a requirement for aftermarket fit hids.
After a search, I came across this paragraph on the website of http://www.h-i-d.co.uk/:
NOTES ON ROAD LEGALITY AND QUALITY OF OUR HID :
Both versions of our HID systems are DOT approved, MOT approved and fully E-compliant in all safety, E.M. emmission and performance specifications. As far as we are aware these are the only HID kits on the market that meet all these requirements.
This makes our kits ROAD LEGAL ; there is a lot of misinformation regarding the legality of HID systems fitted to cars without headlamp power wash and rear axle self levelling ...these are only an E.U. legal requirement on Xenon systems fitted to NEW cars AT THE FACTORY PRODUCTION STAGE .
HID systems fitted as aftermarket accessory DO NOT REQUIRE the car to have power wash or self levelling ; even the DOT get this wrong sometimes .... our expensive lawyers did not ! "