TOPIC:

You mentioned you replace the bulbs. Did you get the correct bulb? It should be a dual element bulb similar to an 1157. Try removing one bulb at a time to see what the other does. Somehow you are getting power to the blue wire. Either through one of the brake light switches from the brown on that switch, Which is 12 V power or you are getting power from the red which is the tail/running light circuit. The red is energized through the ignition switch.

Will get back to you on that .

I missed your post that yes the brake light comes on with turning the ignition on. That means you running/tail light circuit (Red wire) is powering the brake light circuit (blue) wire. Check where the wire pass thru the tail light bracket. 
 

.....am still betting on the rear brake switch.......  

Hi, the brake light goes out when the rear switch is disconnected but it stays on when the front switch is disconnected.

Yeah, you need to adjust the rear brake light switch.

Hi, there isn’t anywhere to adjust, it push  fits into a housing at the bottom and into a wiring terminal at the top, there isn’t an adjustment screw on the switch.

wrote:

Hi, there isn’t anywhere to adjust, it push  fits into a housing at the bottom and into a wiring terminal at the top, there isn’t an adjustment screw on the switch.

correct, so then there must be an adjustment in the rod connecting the pedal to the master cylinder or a stop bolt on the frame that adjusts the pedal 

 

Is this spring in place. Looks like it returns the pedal to the up position. Maybe it broke and that’s what started your issue

 

Doesn't the switch body screw/unscrew in the middle to change length???       Or could the mounting be displaced?

 

Thanks, there is definitely a locking nut under the rear brake cylinder but I was wary of undoing in case brake fluid escaped, I will also check the spring.

Hi, no the switch is solid as is the metal housing it clips into.