I wouldn’t doubt if it’s just good enough and it’s expensive to add the insulation to old buildings let alone stone/brick ones. But I’m not going to pretend I understand what life in Britain is like or what homes are generally like when I’ve never been. I was going to say that buildings might be substantially older but honestly I don’t know how old the average home is in Britain, most people could live in something made in the 70’s or newer like here in the US.