An interesting topic...as someone who works in the food industry I feel I can say that British sourcing is very high on a lot of shoppers minds at the moment and therefore presumably British travelers minds as well, so BA could probably
play on this more. However, a lot of premium customers are not British and as there is little/no choice once you're at 36,000 feet, if the quality and price of a foreign product is right, then BA probably see little to be gained from British sourcing.

I actually have a case study for you of this as well... our famous French made conserve is In the process of replacing a British made equivalent on the Club World and First menu because BA thought our quality was better (and it clearly is). However my company have also had this conversation with another leading British long haul carrier and they will not stock our products until
they are made in the U.K. - quite litreraly food for thought!