lbschenkel To tell the truth my MitID app hadn't been working for months (I would get an error saying "Bad connection to MitID").
Fortunately I had followed your suggestion of getting a code viewer long before this happened.
But Duckduck 's advice of temporarily reinstalling GPS after updating the app has restored it to life. Thank you very much!
It does however seem that now (unlike what was the case when I posted my previous comment) the Google apps need network permission when you first open MitID after installing/updating. As soon as MitID is in a working state the Google apps can be uninstalled / have their permissions revoked (like Duckduck said).