Im probably being thick here, but if you connect a bulb across the battery terminals it should light up?!
Ive tried it including an electrical screwdriver with test lamp, the test lamp lights up which means there is a complete circuit, but the actual bulb isnt?!
Ive tried it with 3 different ones now lol
I just want to check the actual bulb is working so i can rule that out of the problem

 

it should yeah

flat battery???

 

Get a multi meter and check continuety across the 2 terminals...

 

stick it in your ear, it should light up! ... well my grandpa used to do it!

 

this isnt an LED is it?

 

Think im getting somewhere now, its just a normal sidelight!
Must be a dodgy earth as when i bridge it from the main bulb it works