I had noticed the brake lights weren't working again (maybe I should wire in a warning light for brake light failure). I assumed the switch had simply vibrated out of position so fiddled with the mounting, wiggling it about a bit).
And I was right, lights now working again. This is a bit hit or miss,
and as you never normally notice if the lights are working (I suspect
they just work for a few days before the MOT and a few days after )
In the long term I need to come up with a better solution, so the
mounting is rock solid and there is some sort of proper adjustment on