I have had a Trident Exel Fan Powered Gas fire fitted in my living room since moving into my new build house about eight years ago. We have only used the fire a few times since then. I am getting cavity wall insulation done and the fitters need to see the fire working as part of their checks. It wouldn't switch on. The pilot light works okay and the fan also works okay but the gas illumination light does not come on and subsequently the gas does not come through. Is there any checks I could do in an attempt to get it working prior to calling out an engineer?