I have been trying to find out how headlights control the dipping but without much success so far. I have been trying for over 2 years to get left hand drive headlights for my LDV Convoy van but there are none available. I want to get the UK van registered on Hungarian plates but they insist I change the headlights. I'm wondering if I modify the existing lights so that the bulb holders go in the other way up, would that change the dip direction from left to right?