Doesn’t surprise me about BA, after all, being a European airline, they probably don’t get the African knack of wearing practical dress. I wonder what would have happened if a Maasai warrior was behind you in the queue, re-splendid in traditional dress.
As for staff travel, I can’t remember CP ever having a code, I’m sure they must of, and we did fly other airlines, including KLM quite frequently, so I’m sure they must have. Back in the day, Sunday attire was the order of the day when flying !!