I am installing a 12v/gas fridge in my camper,& would like some advice re the gas installation, there is an outlet on the flue, rather than drill the bodywork can I dangle a flexible pipe out the window, does it need to be as high as poss above the flue? is 1 vent adequate as there is only one outlet on the fridge.do I require a gas inspection, would it be ok to rely on a carbon monoxide alarm.thanks all.