Bachmann (with Vitrains PCB) Class 37 lighting/wiring

[forest2807]

Is anyone able to offer advice on my wiring problem? I have cobbled together a running chassis out of various Bachmann spares to go under a spare Bachmann body, but as I had a Vitrains PCB in my spares box I thought I’d utilise it. 

The problem is at the right hand end as you look from above. The hi-intensity headlight and the marker lights work in the direction of travel , ie to the right, but when the current is reversed and the loco travels towards the left,  the tail lights at the right hand end do not work. Can anyone see if I have wired them to the PCB correctly? All lights at the left hand end work as they should.

I have used an alternative bodyshell to rule out a problem with the lighting board inside the nose of my bodyshell, and the problem persists so I am assuming it lies with the wiring/PCB.

Any advice gratefully received.