I have two 1991 MK consumer units, each with 12 used MCB slots. It is a big house, and when we bought it, there were three fuse boards, one for each floor.
One of the MK's has loading on it for a cooker (45A MCB, 6mm T&E), an immersion heater (32A MCB, 2.5mm T&E), heat pump (45A MCB, 6mm...