Excuse the long title but we have recently moved into a 1930’s bungalow of cavity construction and have some ventilation issues to sort out - surprise surprise. Only 2 of the original vents remain and they are badly covered in concrete from the poor rough casting and a third is placed above the dpc between floor joists by the looks of it. Overall I’m looking for around 10 double air brick vents to be fitted correctly and so I am trying to find a builder with the relevant experience. I’m not having much luck searching so thought I would try here on the offchance. Anyone?