Incase it helps others
iPhone 12 Pro Max - using to do doc upload for job. Got through to the bit where it was asking me to scan my passport nfc chip. Pressed to do so and it just got stuck repeatedly saying I don’t have the app and to download and then come back. Thankfully a previous reviewer had posted up their advice that you will need to start again, shut the app completely by swiping up from bottom of screen and closing and then restart your phone. Once I did that it worked, although for the passport chip part you have to put your phone against the photo page. Seems as though plenty of others having issues with this app, and this might help someone else in the future. If the app worked as it should do then great idea, but this is a pretty major bug that will presumably throw a lot of people.