I'm married to a Kiwi, and my brother-in-law is over here at the moment AND living in London.
The major advantage of moving to London is the simple fact that you'll find loads of Kiwis and Aussies there, and there is a thriving Anzac community in London, so if you feel uncomfortable about moving to a new country you'll find a lot of your own countrymen and women in one place........which is useful should you wish to enjoy your rugby at any point! :D
Jobs-wise over here at the moment it really depends upon what skills you have, and what you can bring to the table. My Brother-in-law has only just got a new job in London, and even my mother (at 61) has just managed to get a new job out in the boonies, so ignore the doom-and-gloom merchants. Basically if you're willing to work, and have a brain between your ears there are jobs over here. The only thing that might hold you back is whether or not (like my wife and brother-in-law) you have the dual nationality and therefore hold a UK Passport as well as your NZ one. My wife has no problems with that as she was born over here and moved to NZ at the age of 6 months, but I know my parents-in-law had to take up the option from the NZ Government at sometime to apply for the dual nationality for my brother-in-law. The usual 2 year Visa otherwise given to Kiwis does make it tricky for employers looking to take people on for more long term contracts, and will put you at a disadvantage over others when applying for jobs, especially if you aim for work outside of London.
Otherwise you'd love it over here! :D The only thing is that you'll find it weird watching Super 14 whilst having your breakfast on a Saturday morning!
Whereabouts you from in NZ? Not a Jafa are you? lol :P