I have made a mistake - I blocked up a kitchen fireplace - but forgot the airbrick and now there is damp showing - I can fit an airbrick no probs but then I figured why not just drill about 7 or 8 1 inch holes and screw a adjustable grill over the top - an adjustable DIY grill. Can anyone see a problem with that... I think it will be quicker and easier than fitting an airbrick ???