HI guys, my UK Nokia E51 and GFs E71 are both locked to UK networks and we want to use them with NZ sims. Where is the best place in Auckland to get them unlocked? (Mobile shop on the K Road?)

Also, whilst I will obviously take a back up, am I right in saying that in theory the data should be left untouched by an unlock? Is there anything else I should be careful of?

FYI they are on TMobile, but contracts have terminated - so not only will T mobile not unlock them but also it takes 28 days and I don't want to wait that long really.

(Should have had them done before I came - most high streets in London has stalls etc which will unlock phones for $18.  I gather it is more likely to be $50 here!)