Do you have openable windows.
If answer is yes, when fire is turned on shove head out side and breath fresh air coz i,m sure you aint checked any gas pressure or gas rate ect, so cannot determine if fire is working safely.
Just incase you were not aware, faulty , badly or illegaly installed fuel burning appliances can give off carbon monoxide, but reading your post I asume you dont care a dam.
You may soon be another statistic that HSE can inform us about. RIP