Restricted acces Other and the Moodle app

I'm struggling to get LOs that are published using restricted access set to other, to open when viewing through the Moodle app. I can't seem to find any advice on the app forums or any detail around the url the app uses. There is a thread on SSO with the app that suggest it is //yourmoodle/tool/mobile for authentication so tried this without any joy. Also tried the older local/mobile and no luck.
Does anyone have any suggestions as to what the url might be?
I appreciate there are other ways around this but this fits better with my other constraints.
Cheers
Graeme