Thanks for being the only person willing to help!
It is an aftermarket LED cluster which came with the car. I have resoldered LED's on the boards to the rear of the cluster itself. It has three boards of LED's. You simply unscrew the PCB's that are screwed into the plastic unit, unclip the wiring and it is free. Sorry no pictures, my phone cable is broken!
I have also tried putting in a new earth to no avail. Brake light on this side is no longer working now either!
Any help would be greatly appreciated