Map update should not cost more than £150, the dealer has to purchase the activation code from BMW they will already have 2011 Prem maps europe on their system. When I purchased my pre-reg GT they did it and s/w update as part of the deal but told me the map activation code would cost them about £110.
If you want to do it yourself....
See
http://www.bimmerretrofit.com/forums...331b5442126655