I found it in the passenger foot well (literally). The switch assembly is made up of a white plastic spring plunger assembly and a wiring connector which clip together onto a lever on the braking rod in the passenger footwell - fairly high up. It looks as though someone sitting in the passenger seat had caught it with a foot and unclipped the wiring loom which allowed the spring assemmbly to pop out wjere I found it on the passenger side footwell floor. It all clipped back together OK and the brake lights are now working again. It's a bit of a cr@p design really..............
