Bailey approach

Anybody out there with a Bailey Approach having electric problems with the drivers side high rear light. I have, was told it was how it was wired up this was then fixed!!!!!!!! Still goes out, was in a traffic queue on Friday and observed this light going on when I had my foot on the brake pedal. If I then put the lights on and pressed the brake pedal the rear light would go out, this then re-set itself when the lights were switch of and back on again.  Must be a cross over of currents or something, any one able to comment?..