When you are using the Garmin Ordnance Survey 1:25k Map cards covering all of Great Britain to plan Routes with in BaseCamp you can only select one of the 5 map areas at a time to view on the map page i.e. East England, North England & IOM, North Scotland, South Scotland & West England & Wales, you cannot view all of the areas together only one at a time.

If you are planning a Route that moves across different regions you can select the different map sets as they are needed from the Map menu along the top menu options in BaseCamp software.