I was thinking of using a small BBQ as a test first. I've a spare household fire/carbon monoxide detector. I'm just interested on the safe minimum of ventilation that'd required before people start to fall asleep.
How about a frontier stove? We camped opposite a tentipi last week and it looked fab with the flue coming up through the top. Have to admit to feeling very envious.
Amazing family weekend with old steam engines, classic car displays, market stalls, and full catering and bar. And camping on site - Save £25 by booking in advance.