Leaving the app to one side, NHS Digital has been doing good stuff for the last couple of years: https://digital.nhs.uk/

They do, and there were good people working on this.

That said, my suspicion is that they have good track records of working with open web stacks, and were somewhat less familiar with the realities of working with closed app platforms that relate to hardware integration, and that's where they came unstuck.

Which is why this government is keen to gut it and outsource it all to the likes of Babylon.

The NHS aren't developing it, it's developed by a private company.

If you mean that private companies developing for the public sector in shady deals have a terrible history, I'd agree.