Roy-Foley I’ve not bypassed the red wires, I can give it a go if you tell me how.
Unplug the wires both ends of the stat (thick wires wrapped in cord), then connect them together with a piece of wire - if you have some automotive spade connectors it will be easier, but otherwise just strip and stuff a short piece of wire into both connectors on the wires, making sure there is continuity. INSULATE with some tape - it will be live once the machine/boiler circuit is on.