Ordnance Survey
With an Ordnance Survey API Key entered in the API Keys formatting section, Icon Map Pro can use Ordnance Survey maps as a background map.
Only maps served in EPSG:3857 can be used, which means that the Leisure map is not currently supported. Selecting Ordnance Survey as a map source will automatically set the map's bounds and zoom levels which can be enabled in the Map formatting settings. This will then ensure that you can't scroll past the edges of Great Britain and beyond the available mapping.