License plate lamp and rear left (NS) tail/brake light

[My Evil Twin]

Are they conneted in some way.

was replacing the bulbs in the licence plate and general pissing about then when i went to check they were working with the new bulbs.
nothing.
I had previously checked all the lights about 5 min before as i was doing a pre-MOT check.

do they have common earth? or common fuse?
I might have tugged the cable to better seat the live blade, have i pulled a connector further down the cable?
where is it, next to the right (OS) rear wheel I guess??

thanks

[freebee]

my number plate cable is a single live spur that comes out of the loom in front of the petrol tank it relies on ground through the chassis.