New to caravanning. Help with fridge.

1Tracey1

It's our first time on non ehu and we cannot get the fridge to run off gas. Manual says to select gas, turn and hold temp button in and press ignitor button whilst keeping temp button pressed. However nothing is happening. We cannot hear anything igniting
but don't know if we should or not. Gas bottle on. Gas switch under seat is on. Are we missing anything obvious??