Thetford oven - Won't stay lit

Philpatton1977

Hi,

our thetford oven will not stay lit when we first try to light it. i have tried holding knob in for ages and then slowly letting go, holding it for 30 secs and letting go, and even taking the knob off altogether and pressing the spindle in for 30 secs. The
burner lights but as soon as I let go of the knob, the flame goes out. I've checked the thermocoupler and it is in the flame and glowing red every time. Am I missing something?