Hi,
what model year is the car? Are you using the Connect sat nav (built in phone, i think ) or the older one?
I don't know much about the Connect system, i believe you get a one year subscription to that with the car, and then have to pay after that. I have not used this system so i might be wrong.
The older system, has no subscription charge but the discs themselves do get released and updated on a yearly basis ( i have 1999 and 2003, '99 doesn't even believe my village exists! 2003 knows exactly where my house is)
The older one ( the one i have) has only one code, i believe, that you need to enter when powering up after power is disconnected.
I have seen the little padlock symbol appear next to some of the menu items on my sat nav too ( tourist info etc. , i think? ), which items do the padlocks appear next to on yours?
Sorry to ramble, but i hope some of this helps.