If I were you i'd try and get in on the 75/76. The 777, when your junior will be constant 3 day trips to the E Coast and Middle East. Its the least "Fun" long haul aircraft until you can get some Gatwick trips, which tend to be senior. The 75/76 is doing increasing amounts of long haul, the Cabin Crews are smaller, more junior and more likely to come out and play on 5 day EBB/NBO etc. Also you get some of the better Short Haul nightstops with eurofleet crew for variety.
If you can get the 744, thats still the place to be for the moment.