I'm glad you chose AA. I think they're much better. If you have a V,M,L,W fare then you could get the golkd challenge within one trip. That then gets you pre-booking of exit rows and no-line drive-up check-in at LHR across the street from the main terminal.

IMO AA beats BA in economy without question -- BA is an airline aimed solely at people on premium tickets, and they persecute their coach passengers accordingly. AA is a much more pleasant experience.

Take your own food if you want to eat. Airline food ranges from bad to mediocre, and food in business class is nice but nothing better than you could bring yourself really (although I'm a fan of AA's warm nuts and their cheese plates myself, as well as the pleasant service).