delonghi dfs090d0 main oven not getting hot ?

Hi, the problem we have is the main fan oven not getting hot. The oven has two elements, a top element for the grill and a circular elemnt around the fan and its this element that fails to heat. I've changed the element to know avail, check continuity on new element just to be sure and ok. Power is getting to the new element at both terminals so i think eliminates thermostat and main switch. Also checked thermal cut out and continuity across both terminals. The only thing i can think of is if the thermo couple attached to the thermostat is broken, have checked and can see no obvious leakage. Anyone with any ideas would be much appreciatted, thank you.

Phil
January 2015