Lighting fault

My MOT is due in a few days, and I've just seen my number plate light ain't working. 
I changed the bulb but no joy, put a meter on it and there's no power getting through, the wire must be broken...

As I haven't really got time to strip the back end, any ideas where I could run a temporary wire to just to get it through the MOT???....... Cheers

I'd tap into the back light wire then sort it when you've had it mot'd.