This is a thread that I find difficult to place, because it just doesn't compute against all my BA flying experiences. If there is space in the overheads, then there is no need to use the floor, and if there were 3 hat bins with space in them there is zero pressure on cabin crew to get things on to the floor. So if this happened as stated, and you were only flying with 2 modest sized bags, then it's just down to a particularly eccentric member of cabin crew who you will have very little chance of flying with in the future.