With respect, I did my part of the bargain here. I paid for my ticket, turned up at the airport at the time requested and handed my bag to BA. The only party who didn’t do what they were supposed to do here is BA, by failing to put my bag on the plane.

Obviously I’ve learned an important lesson that trusting BA with anything you actually need at the other end is a good way to f up your holiday, but I don’t think it’s too much to ask that they actually make some sort of effort to rectify their mistake.