Wrap up on the RTW with Air NZ.
Thanks to all for advice and it is much appreciated. Some of the touring suggestions are also of interest and will be explored further.
The final itinerary was dictated by family considerations and was a less adventurous one than initially aspired to (strike one to Mrs L). It wound up as DUB-LHR-HKG-AKL-BNE-AKL-SFO-LAX-LHR-DUB.
By far the best deal was dealing directly with Air NZ. Our well established and efficient travel agent tried hard but could not remotely match the Air NZ deal -almost 100% dearer in fact. We opted eventually for a 50:50 mix of PE and Business and it worked out a bit over STG6k. Trying the Star Alliance own website just did not work for us - possibly our location is penalising us. Anyway, the wanted itinerary seems to be unavailable other than by using Air NZs own direct sales.
A few points of note. Booking a United leg from SFO to LAX seems to show some funnies with their booking engine. Possibly integration with Continental is not fully established yet. Also, Air NZ allows the booking of tickets up to 350 days in advance whereas their Star partner United will only allow 330 days - this makes lining up all the ducks a little fiddley if you book very far in advance. Finally, Air NZ's direct sales folk were a pleasure to deal with and worked hard to pull it all together for us, even suggesting some cheaper options where they were available.
We will spend about 12 days on North Island and leave South Island and the bungie jumping for another visit. Any further suggestions will be appreciated - particularly any "must sees" re North Island.
As a postscript, just looking at the Air NZ hardware in use one wonders if their 744s will be heading for the old folks home soon? They are still in use for AKL to SFO (and BNE to AKL!).
Again thanks for advice to all. We look forward to an interesting first trip to HKG and NZ.