Alan, have you got any more of the photos of the original wiring of the tea urn, only I've managed to remove all the wiring to fit a rheostat from a cooker this failed miserably. I was going to rewire it back as it was but have,t got a clue, i might have been better fitting a rheostat the same as yours. There's no problem if you have,t because I will fit kettle element and a PID.