problem downloading NHS Covid app onto Iphone XR

thete is problem feedback here

https://faq.covid19.nhs.uk/create-case/

or you could restore your phone to get rid of whatever is corrupting it

Not a small job

Here is a guide for those steps:

How to back up your iPhone, iPad, and iPod touch

Restore your iPhone, iPad, or iPod to factory settings

restore from backup.

Yes

First step backs up all your apps and data

Second step takes it back to how it was out of the box

Third step puts all your apps and data back but hopefully not rogue junk.

What takes the time is signing back into your bank accounts and apple wallet etc.

Make sure your photos and documents are imported into somewhere else like a computer in case step three fails

First plan is contact the developers in that government site

What problem are you experiencing?

The app is enjoying 4.6 rating on App Store so it is unlikely to be a general problem

Do you live in England or Gib?