Hi there, thanks for the reply. It has to do with the booking classes. For example A RWT on * is economy on some airlines and discount economy on others. They don't work with mileage for determining tier status but give you 'status credits' of which you only get 50% (!) when not flying premium economy.

Thanks for the AC tip - someone else mentioned that too. I can't really use their miles out of NZ but I guess the 35K 'buys' me *G status and then I can earn the other points on another airline.

A site I found, which everyone probably already knows about) is www.ukstatus.co.uk which, if you are a UK resident, let's you switch and keep your status and even gives away 5,000 bonus points to the 'switcher' and 2,000 to the 'switchee'.