Thanks Mike and Swinks
I have thought about a plywood option which would obviously be more durable but I was thinking the wood grain may show through the paint? I am trying to achieve a smooth as possible finish. As you mentioned Swinks the 12mm fits petty well with a very slight step which could easily be sanded down. My concern with the 12mm MDF is the screws holding the circuit board plate were there is no wiring loops showing through the back. I could pack them out with a washer I guess. Even the original must of been close to showing with only a 0.7mm difference.
Maybe the best option is to use a shorter screw as the ones that came out are 1/2 inch.
