For sure there will be some difference between HIDs and LEDs does, but I think it would be imperative to get to the bottom of this - I've tried to get to the source but not sure where to start. I would imagine it's based on EU regulations, or directive transposed into UK law, but reading articles about led retrofits and how illegal these are never actually mentions any legislative piece - does anyone know? Not sure what's the main motor law in UK?This bit isn't entirely accurate....but it's the legal requirement for led lights to have auto leveling, which with retrofit it does not.
If you have a car with factory fir HID/LED bulbs and there is a self-levelling system fitted, it MUST be operational. If the car does not have factory fitted self-levelling, there is no requirement for it.