Rear wiper on 2008 Scout estate not working

Hi all,

I have a 2008 Scout estate and the rear wiper has stopped working.

I have had it out, and apart, and tried 12v straight to the motor with the PCB removed and nothing happens.

I bought a cheap used one from EBay to try a straight swap. Still nothing.

I have searched the forum and figured out:

Water ingress - looks very dry and washer is in the brake light, so maybe not.

Tailgate open - Still nothing with it closed.
Switch in the tailgate lock - where is that? And what am I testing for? The boot light isn't on as far as I can tell. But I do get water dripping out of the lock and down the back of my neck when I open the tailgate. Is that a sign that the lock/lock switch if the problem?

So on the basis I might also have a dud replacement motor, is there an easy and simple way to test it without frying the PCB? What power and signals does it need in the plug?

Can I check if there is the appropriate signals from the loom?

I also have an MOT coming up. Should I just 'delete' the rear wiper altogether for that and deal with it after (is it even tested)?

Thank you. (Goes off to search tailgate lock.)