I can save the route file to  cloud based storage and then copy to the SD card but this relies on a Internet link.

There is no option in Skydemon to save route files locally - 'save as' does not save locally. Send by email does not create any local files. I have installed different file and email systems to the tablet and this has made no difference. The Skydemon manual does describe how this all should work but I think its guidance is out of date. I have tried different Android devices - Samsung 9+, Samsung tab A, Huawei tablet.

Any ideas?