A lot of people I know move to London from New Zealand and Australia. The question is always whether to buy return tickets or a one-way. Return tickets are generally better priced than one-way tickets, but are only valid for 1 year, so if you don't plan on going back home within a year then they might just be a waste of money.
I've just come over to London myself and bought a one-way ticket through Korean Air. The reason I felt this small fact was worth writing about is not only because the ticket was very well priced at $1000 AUD but also because of the small perks we got while on the journey.
The reason that Korean Air tickets are priced so well is that they generally include a one night 'involuntary stop-over' in Seoul. A lot of people naturally think that if they have to fork out for a night's accomodation in Korea then the price of the whole journey isn't so good anymore. This isn't the case at all - Korean Air actually put you up in a REALLY nice Hyatt Regency, give you dinner, breakfast and lunch vouchers and they also take you to and from the hotel. So you really don't have to pay for anything during your stop-over. Pretty neat eh?
So if you are thinking of flying across to the UK from Australia or NZ and are looking for good prices, don't discount Korean Air - not only did they have good service and food on their flights but they also really look after you on the ground AND you get to stay at a fancy hotel for free!