Cannon Pearl Double oven

Hi
This is follow up to an earlier message where I wasn’t getting a spark in the lower oven. I disconnected the power and gave the area a light brushing. The spark has returned and lights every time but the height of the flame doesn’t alter after the initial low flame at start up. Should the flame visibly get higher/lower as I turn the knob? As well as that if I push the knob in sometimes the flame cuts out but starts up immediately.
Any advice more than welcome.

I can’t find the model number.

Thanks

M