Just to close this off:

ISSUE:  Using the QBO app on mobile phone, managing trips would be possible sometimes when making journeys.   Trips can be categorised etc. But this would only appear during journeys.

There were no control options in the App to access this feature.

CAUSE: The app should not have been tracking journeys as I am not Master  Admin.  This feature should only appear for Master Admin only.   

RESOLUTION: After I un-installed and re-installed the App, the ability to manage trips has now gone.  Likely to be a corrupt configuration, fixed by the re-install.

(Other bugs are introduced by re-install though: Dashboard says "you have 3 unpaid invoices" tap to see them says "you have no unpaid invoices".    Dashboard has a blank area where Profit and Loss tile is drawn but not painted.)