A relative of mine who is RHS on a well known South African carrier, confirms that BA regularly hold up the taxi queue. He said that, a few weeks ago, they were behind a BA744 at the CPT hold and had to wait for 32 minutes whilst BA 'Got the numbers'.
The whole queue had to wait as BA were blocking access to the active. So BA mgmt might like to rethink how they do this and save delays and risking that someone might be head down at the wrong moment. (Not withstanding that the Cpt carries the can on this. As I have said, the BA mgmt will not get punished and the ACSA mgmt that have not put suitable width restriction/turn signs won't get punished either
)