satellite navigation

Hi all, Can anybody advise me of where I am able to get a sat nav cd for an E280 Sports, 2006 plate? The new ones or Merc aproved ones cost around £200! Thanks :)

I have the full command system in a 2006 ML320. I have both sat nav discs (UK and Europe). I live and do most of my driving in London and actually keep the disc in all the time. However it is very vague at finding the correct road/destination - even if I type in the postcode! Surely if I type in...