It might be the potentiometer
Which is what?!?!
Tried a different coolant sensor on it but that wasnt new either so spose its worth a go getting a new 1 just to see couldnt hurt................
WIll have a look at the codes on the ECU and get back 2 u mate
Actually rememeber the car was running shit for a while before it eventually gave up so, not that helps much now but still