Hi VFE,
Yesterday's HKG LHR flight (with RB211 engines) was into an abnormally weak headwind of only 4kts average, so these figures are unusual:
TOW 358000kg
Trip fuel 120000kg 12.00hrs 5550nm
Cont 800 kg 0.05min
Div 3800kg 0.20min 80nm
Res 4100kg 30min
Taxi 1200kg 25 min
TOTAL 129900kg
As far as fire extinguishers are concerned, the RR engines have 2 extinguishers per engine and the GE engines have 2 extinguishers per wing.
On the RR, you cannot cross-feed any engine's extinguisher into another one on the same wing, let alone across the wing. But as they have two each, I guess it was considered unneccessary.
On the GE engines either of the two bottles can be fired into either engine on the same wing, but you cannot cross-feed across to the other wing.
Don't know about PW engines.
Ball-park fuel flow for RR at heavy weight is 12000kg per hour initially, then after 12 hours it's down to about 8000kg. Taxi fuel is 2800kg per hour.
Hope this helps.
Eck