I see your mould and raise you a bird.

We once had a bird get into the house through a hole in the wall intended for a kitchen exhaust fan. Whoever had installed the kitchen hadn't 1) connected the exhaust hood to the hole in the wall, or 2) covered the hole on the outside wall. The hole was above the tops of the kitchen cabinets, so we didn't know it was even there.

We once had a bird get into the house through a hole in the wall intended for a kitchen exhaust fan. Whoever had installed the kitchen hadn't 1) connected the exhaust hood to the hole in the wall, or 2) covered the hole on the outside wall. The hole was above the tops of the kitchen cabinets, so we didn't know it was even there.

Our house is full of holes like that.  We'll sort it out when we get the render re-done.  First we'll tackle the outside, and then we'll go room by room inside.  By the end of it, I hope to know ever square inch of the place, and we will seal things up properly, or put vent covers where vents exist.