NZ only does the AKL-LAX-LHR leg. QF only does the Australia-Asia-LHR routes. QF has tried to get the other leg by getting one of BA's 2 LAX-LHR flights, but I think if they don't get such a deal, they wont be able to fly that leg. Probably the same with ANZ, but then again I am not sure. I do know that ANZ consistantly offers some of the best LAX-LHR fares of the 5 carriers that do the route