Got it sorted, I think the tuner might have been have been doing something strange. I mustn't have tried it with it disconnected at the practice space. It seems to be a bit fucked. Should probably invest in a decent one anyway.
I'll need to finish off the board now.
Thanks for the help!
Do you reckon I'd be alright to cut the plug off the power unit and wire it up to a female kettle lead type connection moose?
Yeah no problem. I've cut all mine and replaced them Irish plugs but the female kettle/IEC is a better solution I reckon.
Cool, must finish off the board with patch bays and power etc.
Turns out the wiring in my practice space must be dodgy. I brought my boards sans tuner and the problem persisted.
Tried it through a socket from at other end of the room and voila! Works fine. My tuner is still knackered but thats a different story.