There is the option of LHR-TYO-AKL on BA/JL/NZ return AKL-TYO-LHR on NZ/BA.
There is, but those options are highly unattractive because:
- The JL/NH and 1 of the 2 BA LHR-TYO flights go to HND, NZ flies from NRT. Transiting HND-NRT is less than desirable, especially when the BA flight arrives at 0730 (far too early) and the JL one at 1600 (far too late) to make the 1830 NZ departure from NRT.
- The 1 BA flight to NRT means a 9 hour transit at NRT (the soon to be cancelled VS flight is similar). Given the 1.5-2hr travel time from NRT to downtown Tokyo each way, and the ANA lounge at NRT isn't that great, I'd rather not do that. LAX and SFO transits are not great, but none involve anything like the time lag on an already lengthy trip.
- Westbound LHR-NRT is overnight in PE (and not on an upgradable class on BA), if I go via LAX or SFO it is a daytime sector. NZ Spaceseat LHR-LAX is quite pleasant, and VS has the small advantage of offering access to the LHR Clubhouse in advance of the trip for the SFO route if booking the NZ codeshare.