The fact is that BA long haul have never successfully operated all cargo services in their own right. BOAC started subcontracting ( to Skyways) in the 1940s and their occasional forays into doing it themselves with Yorks,DC- 7Fs, B 707s and later the single 747F quickly sold to Cathay have not been profitable. BEA and BA shorthaul efforts with DC 3s and later Argosys and the Merchantman ( Vanguard) were no more successful, although thet carried a lot of cargo. The same would be if GSS were to incur BA costs, working practices etc,- it would simply fail.