Thanks so much for the feedback and suggestions.
I am not planning on an upgrade - these sectors would be part of an international oneworld business award with Qantas so there would be no extra points needed to get into business class.
I will check with Qantas to see if seats are available for specific dates once i have firmed up award flights to from UK.
These are as rare as hens teeth at the moment so I am not holding my breath.