We sort of get fresh air through part of the bungalow, patio door seals have been knackered for a couple of years, bathroom & bedroom windows will not close fully because the tilt mechanisms are bent, and the windows mist up inside of the double glazing.
The mould guy is coming in early February.
PS. On the bathroom door there is a aluminium vent near the bottom, I took it off to paint the door, and guess what?, there is no hole through the door behind it.