I have recently purchased a 2020 Discovery Sport, and am having no luck in finding out if the build in InControl Navigation system supports importing custom POI's or GPX files. The dealers in NZ have been no help to me with this.
I have tried to plug in USB keys with various combinations of files, and the system does do appear to recognize any of them. I have successfully upgraded the maps to the latest version via the USB, so I know all of the connectivity is ok. I have also updated to the latest S20B software update. Surely in 2020, GPX files should be able to be imported?