Headlight flashes then goes off?

I took out my number plate bulb today to replace it. I've now replaced it and it works fine, however the headlight on the same side now doesn't work. Whether it's a coincidence or not I don't know but it flashes and then goes off. Which assumes it is a canbus system issue. Does anyone know how to fix? As I've done this before to my numberplate bulb but never had an issue.