Just for comprehension: BA doesn't serve by row in CE, amirite?
At least that was my impression recently when doing a few returns LUX-LHR. As a silver, I had reserved row 2 each time (due to seat-blocking for Golds in row 1 at the time of booking). Every time, some ppl in the rows behind were served before me and my seatmate. And I saw a few Gold baggage tags in those higher rows. So that may have been what they went by.