Just another thought, when I have travelled with BA in the past and they didn't have my special meal in the cabin I was travelling they would try to find something else from another cabin.

When years ago I did weekly travel with BA, occasionally they failed to pick it up from my customer profile but they always manged to offer me something. OK it may have been more fruit & bread than normal but at least I got fed, which I was happy with!

In terms of claiming Avios I did manage to achieve a 50k credit after I was served a special meal from LAX>LHR with plastic cutlery in CW rather than metal. That was years ago and I was probably considered worthy of the credit given my annual BA spend at that time.