David Aiketgate

Thanks to all inputs. I can now confirm that this does work and will pass the european equivalent of an MOT.

The upshot is that you can disassemble the headlamps and swap the internal glass lenses to achieve a switching of the dip direction.

You need to swap the lenses between the two headlights and reverse them in the headlight to give a right dip instead of a left dip.

The hardest part of the job will be disassembling the headlamp without breaking the adjusters.