in the end I wrote to Enpass Support and received the following response:
Thanks for using Enpass and writing to us.
We are sorry for no response on the forum. The resolution to your query is given below, please revert us back if the issue persists-
Regarding Purchase Restore in iPad-
You can use the Pro version on your iPad as well. Please follow the steps given below to restore the purchase:
Take the backup of Enpass data and save it on the cloud.
Uninstall Enpass app.
Go to device settings->iTunes and App store-> Sign in with the same Apple ID through which you have purchased.
Now install Enpass app from the App Store and check if it is the full version.
If Enpass is still showing Trail version, please follow the steps:
Go to Enpass settings-->Select Upgrade to pro --> select Already purchased.
Regarding Purchase issue-
Please try uninstalling and re-installing the Enpass App from the App Store and then try to purchase the premium feature once again. If the problem persists, please let us know form which country you are trying to purchase?
Note: Before uninstalling the app make sure you already have the backup of Enpass data.
Hope this helps!
Enpass Support Team | https://discussion.enpass.io/
I thought they would also put it in the Forum – but so i have done it myself :-).