Hi Dean,

I only had an hour today so didn't get to try out many options including PC re-boot. The switch did have bits of swarf around it so could be that. It's been on that machine for a while so maybe it's starting to play up.

I'll see if it is OK next time I fire up the PC. I'll also try a new switch and give the terminal connectors a bit of a squeeze before sliding them onto the switch again to get a tight electrical joint.

Thanks