Flickering handbrake light

[HPsauce]

Well I've found the cause.

Decided to have a look through the gap below the handbrake handle and see what was visible, so I lifted the armrests right up and pulled the handbrake on hard to maximise the gap.
First thing that happened was that the trim on top of the handle came loose. The clip at the front end had lost a component in the past and been bodged with duct tape!
Then I noticed a black hard plastic "stop" (about 30mm by 15mm) below the handle. This clearly was missing whatever the top cushioning element was supposed to be; it appeared to have been peeled off.

Looking into the gap I could see a plunger and some wiring, so I thought I'd get a long screwdriver and push the plunger down firmly a few times in case it was just dirty contacts.
As soon as I touched it the wiring plug fell off. Presumably someone had been in there doing some work and not pushed it back on properly.

I can't see the contacts the plug fits on to, and manipulating it through a small hole will be tricky, but if anyone has a diagram I can study I'll think about giving it a go.
I've tried searching for an image of the switch that might help, but not found one yet.