As a tip think about starting the trip somewhere other than the UK - it's a very expensive place to start a xONEX (A OneWorld RTW ticket) in business class. It takes a bit of effort in terms of e-mailing places like Croatia or Egypt but well worth the hassle to save yourself a tidy sum.

In terms of routing an xONEx isn't the best for the Pacific - it only offers Hawaii, and then only as a stop between Oz and Ameriva (or v.v.). If you want to visit one of the other Islands then the best advice may be to do a sidetrip from NZ on a seperate ticket.