Eddies, if the two policewomen had gone to each other's homes and looked after the children in the children's own home, the question of being a child-minder could not have arisen ! As I say, in this case it shouldn't have arisen anyway. It has because some idiot hasn't understood even the law that applies to the situation that did exist, but Buenchico is perfectly correct in saying that, had each policewoman been in the other person's home to look after that person's children no breach of the regulations would have occurred then.
It follows that a baby-sitter is not in breach of the regulations,since a baby-sitter is looking after a child in the child's own home. The same applies to a friend who looks after children in the children's own home.