Cheers RCGF,
I'm in London for a few days so will check this out when I get home.

Memory suggests I've 3 buttons, I just can visualise/recall seeing the rotary knob, or the headlamp water jet button (what a cool place to put it) ....but I've barely sat in the car this year so could be wrong. However, as I've a whirring motor from the right headlamp I guess that can only mean I do have a euro/UK spec car with the automatically adjusting headlamp unit....right?

That aliexpress part does indeed look like a similar part, and for £10.91, (with a £3.62 discount on orders over a whopping £4.52) it has to be worth a punt ;-)

Deactivating the motor is exactly what I'm hoping to do. From my untrained eye - against the garage door - they looked fine, I bet they are, but I obviously don't want the motor engaged constantly. Anyone know if I can simply pull a fuse to stop it?

I may still get it fixed properly, but this may at least enable me to get an MOT and take her out a few times before the salty roads come.