Just a reply for those who may come across the same fault, with Neils advice i had a poke around the right hand side footpeg hanger. Follow the route of the wire and it leads to a micro-switch. When the brake pedal is pressed it releases a small metal spring strip that holds in a tiny button on the micro-switch. Squirted some wd40 on it and and got it to work with jiggling it about. Saved me buying a new switch or even worse paying someone to fix it for me.