In standard situations, to the best of my knowledge BA have never compensated for delayed baggage if it's just some minor hassle factor. They may if there are some exacerbating circumstances, the case I'm thinking of is someone whose wedding dress didn't make it for the ceremony. On the other hand assuming this wasn't on the return leg home, BA are quite generous in paying for unavoidable expenses such as toiletries and clothing if that is the inconvenience factor that is at stake here. And that is indeed in the Montréal Convention. Just fill in Worldtracer and it will come to you in due course.