None of the stands or gates at Pier 6 are exclusive to BA. The computer systems are on BAA's "CUTE" multi-user gateway and it is not unusual to see "First Choice", "Etihad" or "Astraeus" on a stand previously occupied by a BA aircraft.
In fact none of the North Terminal stands are "exclusive" to BA. BA has preferred stands, which may well change season by season. Currently on P6 stand 101 is shared daily between all carriers. It would be very unusual though to see BA on stand 102.