VRS 170PD Manual Reverse light switch

A couple of times recently my reverse sensors have dropped out briefly with the picture disappearing from the head unit.

Today I got my other half to check the reverse lights which also flash off at the same time.

This to me points to the reverse light switch or wiring.

Is it just a standard plunger type screwed into the gearbox? And where would I find it?

Cheers.