The suggestion was from brandon at evolv. however on testing the board would "latch on" when using kanthal builds , due to reverse bias current on the GRND feeding back and turning the switch back on. addittion of the switching diode solved the reverse current problem and its all good.
No problems with temp sensing as it doesnt form part of the monitoring due to diode protection
yep you have the wiring correct and diodes are a few pence with very litttle in wires cos you can put a short on the back of the switch bettween 1 post and the + led