Do LHD halogen headlights work on RHD cars?
AFAIK they should have that little switch thing which swaps from left to right hand drive?

The switch over levers that you refer to are sadly only found on the projector Xenon HID lights. If you have plain Jane Halogen (like me) then its back to the old fashioned method of sticking the masking headlamp converter pads on the lens.

Even with HID Xenon moving the levers does not gave a true right hand left hand conversion it merely blanks off part of the light pattern the equivalent of masking off the lens and is just for temporary use such as going on holiday or an excursion.

For a true conversion say moving from Ireland to Romania with a right hand drive car you would need to replace the headlamps to those that have the correct left hand drive lenses. This should with Halogen be a very straight forward swap.

Yes that's correct I have checked that with BMW themselves and they have said the exact thing.