You need to update your Nav firmware to V31. See
this thread.
Haha. Now that I re-read that thread, I realize I did this:
On the MKIV systems, if you do the upgrade and then install an older software version (such as going from V23 down to V22.1 and then back to V23) , the navigation system may reset out of USA mode and put you into UK mode. You will know this has happened if you are now receiving directions in yards instead of feet and the "Emergency" option has disappeared from your main menu. The advantage of this is that you no longer have the annoying "Accept" screen to hassle with every time you turn on the car. To fix this, the dealer can hook the car up to their computer and reset the navigation system to "USA".
Actually I prefer yards, but I wonder if this is also the reason my Nav seems to have a weak concept of cities. I'll have to check this weekend and see if I can find this UK/USA switch in Progman.