UK LS430's are fitted with right hand drive dipped headlamps. There are two parts to the beam (from each headlamp). The main part of the beam has a flat top. This flat top should be horizontal, and kept in that position by the self-levelling system on each headlamp; this floods the road ahead without dazzling oncoming drivers or pedestrians. The second part of each beam is a streak of light that shines up to the left. This is far enough left not to dazzle oncoming drivers, but lets you as a driver spot pedestrians, cyclists (and horses!) on the left hand side of the road.
If you're driving on the right, you need to remove the left hand streak from each headlamp.
For about a tenner, Lexus will sell you a kit, but it's a bit rubbish, and comes with incorrect instructions. Here's what to do instead.
You need a bit of dirt on your headlamps, really, to see where the light is coming from. However, at night, switch on dipped headlights, stand in front of each headlamp in turn, and look at what you see. In the centre of each beam there is a dimple on the exit glass. Above the dimple the glass should be lit, from the beam that is shining down at the road. Also, however, just to the left and below the beam you'll see a bright patch. This is your target. While you're wating to get on the ferry, simply use a bit of black insulating tape, or whatever, to blank out this small area. On the way back, peel it off.