Have bought new unit - and it says it's not unlocked to receive the maps I want to send - is this because I need to use the software in the box with it's unlock code rather than the mapsource I already have for the old unit?
You can use the software you have already installed but will need to use the unlock wizard again with the codes on the yellow bit of paper in the new box. Once it's unlocked to your new unit it'll be o.k.