I did ask this question, because I suspected that most large corporates had similar deals with several airlines or bulk-bought without regard for carrier through a TA: http://www.flyertalk.com/forum/briti...ht-policy.html

There was one who was "BA or you stay at home" and a few whose employer/client strongly preferred BA but it seemed most respondents had a wide choice of carrier even if they had rebates from BA.