Update:

Managed to get a fair bit work done on building the new footswitch, got all the mounting holes in the diecast Aluminium case drilled, everything seems to fit, drew up a circuit diagram for the new footswitch but ended up making two revisions to it, I think I've pretty much got it all correct, found a downloadable pdf in a Peavey forum today, which saved me a ton of frustration, so it's all ready for wiring up now, will post some pics soon.