Thanks Simon, I didn't think about the capacitor. I ve got some 3mm copper to make a new control plate but I d like to able to revert back to the original if I struggle with it. I ll do a dry run with all the wires tonight and see if there is room, I am pretty sure its deep enough already to get everything underneath but will see. Happy to swap the switch back around if needed but would prefer it at the back.

I won't drill an extra hole for the ground under the bridge you ve given me plenty of other options to try instead. Thanks again

Alex