Bridging the 2 wires that attach to the switch and all good so isolated the problem as the switch.
Checking the switch with a multimeter and again no issues and when I plug it back in again sometimes it worked and other times not or the further the switch was actuated I'd loose signal.
Next option was to dismantle the switch and use a jewellers screwdriver to unclip the top off the body.
Inside the switch is just like a set of breaker points from a pre 1980 ignition.
I simply cleaned the 2 contact faces with a little wet n dry, clipped the top back on and bingo
The screw that fixes the switch to the front brake lever locks the top Inplace if for some reason you manage to break all the plastic locators or you could run a touch of sealant if you choose.
Just be mindful there is a small spring in there but it shouldn't unclip itself but I played it safe and when I lifted the top off I did all this inside a large freezer bag just incase something sprung out.
Maybe a bit of overkill but I didn't want to go hunting over the garage floor for something that could be within a 6m radius.
