I have no doubt the cabin crew would have reported it there and then using the iPad that's carried on every flight - they are as embarrassed by the airline's failings as we are sometimes outraged (albeit in this case it sounds like the catering company's issue, but as BA's contractors they still need to deal with it).

Unless they proactively applied Avios compensation (which they could do for BAEC members), you wouldn't hear back from BA at all - the report would merely be dealt with internally. Even with an Avios award, you'd just see the points appear - there wouldn't be a written explanation.

If you want to pursue this and receive more information (although don't hold your breath as regards its relevance!), as has been said you will need to let BA know yourself via the form on BA.com.