I have this air brick which used to have an adjustable vent over it. Just wondering if I need it or if it can be bricked up? My understanding, which may be incorrect, is that it is to ventilate in between the the inner and outer walls. The property is 1930s and has no cavity, just a small gap between the two walls which is actually pretty much blocked up with cement and other ****. I don't believe this room ever had a fire. I kept it closed for the entirety of the last winter and didn't really suffer any damp problems. Can it's function be removed by either opening a window or a trickle vent? Or is the fact that it ventilates the small space between the walls important? Could I brick it up on the inside and leave the air brick on the outside? I have lots of other air bricks around the property that do not vent internally. Thanks in advance.