Thanks for the advice. This is what we've decided to do (will just get one Skycouch row and then have the window/middle seat converted, and mum/dad take turns sitting on the seat on the end ... I'm happy so long as I can get a chance to watch a few movies in peace, which isn't as easy as it used to be).

On a side note, does anybody know if you can book a flight for a baby who doesn't yet have a passport? Passport is processing so we know the exact name/DOB details (not like we are booking for a yet-to-be-born). I can't find any information about this on the Air NZ site and the call centre is taking forever, as is the travel agent we are trying to arrange accommodation through.