Think you should be able to make it work with RouteBuddy, I’m trialling atm (iOS)… The online maps are ok if you have good signal(haw haw), however you can download any OS sheet in the usual scales to the device. In other words, OS 1:25k map, gps, tracking, compass, waymarkers, exportable routes. Maps are pricy though, 20£ a pop, but then it’s in your pocket. Paper map Killer.