potterton netaheat 55e turning on pilot light - reset button stuck?

In a previous thread for the 80e (which is a larger version of the 55e), a question was raised:

"I have a potterton netaheat 80e and the instruction on the furnace said to turn off the switch for 5 min then turn it back on and the pilot light should come on. It didn't is there another way to get it to come on?"

The response was:

"it is very possible that your boiler has overheated underneath there is a red button push this button back in and hold it a couple of seconds then see if it ignites"

My problem is is that I tried to push in the red button and it won't push in. I can pull the button out, but it doesn't seem to go anywhere when you push it in and the pilot is still not igniting. I see that the limit control panel is set at 160 while the indicator on the reset button is at 200. I think the limit control panel needs to be set higher so that the pilot light will ignite again, but have no idea how to do this if the red button won't push in. Does anyone have any suggestions or know of another way to reset the system?