Even if QF cant get a B777 that will do LHR direct they are a great replacement for the ageing B744 fleet and the B777-300ER will carry some 350 odd pax from Asia to London or Frankfurt for alot less than a B744 can.
The savings on fuel as well as initial depreciation will save QF a fortune alone.
Add to that flexibility across the Pacific (even ETOPS) if needed and to Asia.
Its an outstanding aircraft - especially to replace the A330 which is payload limiting on certain sectors as QF has found out to ports such as India and China.