THE FUB
For your information A B747-400 is operated by a 2 crew flight deck. The BA operation carries an extra crew member for in flight relief due to the Duty Period Jnb-Lhr, and may not have been in the flight deck at the time.
The BA 744 SOPs do not include another crew member in any operating drills, although any extra crew members are obviously useful as a extra pair of eyes when available.