Tim, you are star!
I now have everything working however, I'm somewhat baffled by the switchgear before I took it apart!
In short, it appears to be a non OEM part and was missing parts compared to the one you sent me. With a bit of dexterity, I managed to fit the button, spring and mini pcb board from your part and resolder the wires accordingly. Needed to tap one hole for an M4 screw. It certainly wasn't easy but far easier than trying to remove the cables from the inside of the handlebars and replace once fixed. Starter now operating and I'm ready to pop a bit of oil in the rebuilt engine and test the oil pressure.