I've never heard of this guy James Martin.
Usually, it's some form of marketing gag. The meal is still prepared by the same airport caterer. In order to make the appearance of a higher value, the caterer enters a contract with some (perceived) luxury hotel or famous chef to be allowed to put his name onto the meal. The hotel/chef may receive 1ct per meal for the privilege.

Talking about breakfast, I thought BA "enhanced" (cut or "cruz"ed away) the second meal on most longhaul routes.