[Graham]

Sorry about the GTO. It might be the cable connections into the guide, although I thought I had glued then in place. 

Time to get the 250 LM running next time!

To be honest I wonder if the "glue" is causing the issue, I have not heard of this practise before, maybe others do it ?
But my experience is that mostly the wires are just physically held in place within the eyelet or some people do solder the wires into the eyelet, but even this often causes the wires to become too brittle and break off.