In the process of doing up my kitchen, and I have three airbricks/holes in question...
One is below the level of the worktop, and is adjacent to the gas main (no longer in use, the new gas main runs up outside the flat) coming up through the floor (first floor flat). This was blocked up with cardboard. I could see no sensible purpose for it, plus it looked like the exposure had in the past caused a pipe to freeze and burst, so I filled it with foam, and insulated the new pipes I installed which ran past that section. Before I fit the worktops, and therefore remove all access to that area, is there any reason why I might want an airbrick?
The second is in the kitchen cabinet containing the gas meter. I've retained that one, but when I put the new cabinet in I installed an adjustable vent instead of a permanently open one. Anything wrong with that?
The third one is actually in the living room, and I think it might be there because there used to be a gas fire there too (and a back boiler). I've got two options here:
a) Install an adjustable vent for appearances sake and fill the hole with bubble wrap... b) Fill it with foam and paint over the hole thing.
I'm inclined to go for a) but b) would obviously look better if there's no purpose to having this thing at all...
Ben