For what it's worth, I managed to book the flight I wanted yesterday AKL-PEK. My experience, having watched nearby days as well, is that NZ open up seats again 30 or 31 days out. From zero, I was able to book 2 seats and there are 4 more free.

Agent was a bit confusing about the re-calc of YQ. Guess I'll have to watch my statements and maybe call PTS.

If anyone is trying to get to NZ with a combination of Avios (+241) and bmi I think this is a great option. LHR-PEK is 150k+voucher for 2 in F now, and then it 37.5k bmi +£120. We're also stopping in OZ; shame we don't have time for another Asia stop on the way back.