Finally! But some questions...

That is correct, in the UK you can only fit a LED bulb in to fittings which were designed for LEDs, not retrofit to fittings designed for halogen. This applies to all external light units.

It doesn't stop retailers from selling them or people fitting them, but the better retailers state they are for off-road use only.

It will be an MOT failure, if the tester picks up on it, so I guess people who use them swap to a halogen before the MOT.

Robin

wrote:

I thought that ther was a prohibition against fitting an led element into a lamp unit not specifically designed for such a thing.

I'm not familiar with the wording of the relevant legislation in the UK, but if it's like the US, the requirement will be that the light source (incandescent filament, HID or LED) has been tested in the lamp fixture and certified as compliant with the regulations - the fixture may have been designed for a filament bulb, but if someone were to develop an LED replacement that mimicked the output of a filament bulb, it would theoretically be possible to certify the replacement.

Whilst this has been attempted before with both HID & LED bulbs in headlamp fixtures designed for incandescent bulbs, one of the short comings has been that final positioning of the replacement bulb was left up to the installer, making it not only possible but very easy for them to get it wrong, and this I believe is one of the design factors that Osram has found a way to deal with.

In this particular instance Osram is providing a list of vehicles and the countries for which certification has been met. - they specifically state that the lamp is not legal in countries where the traffic drives on the left (so UK) and based on my familiarity with the H4 bulbs, it is my suspicion that it is a paperwork/certification issue rather than the beam pattern actually being incorrect.