How to solve this
The standard government approach to this kind of problem is to hire a big company, set a budget and delivery date, watch the delivery date come and go, throw more money at it in the hope of rescuing the sinking project, and finally publish a report saying that the project was doomed from the start by lack of good requirements. If we are really unlucky then the project will get as far as an attempted roll-out where the entire NHS switches over on D-Day, with total chaos when the IT goes TITSUP. We will never get a working IT system using this approach.
Instead the central government should set interoperability standards and then require IT suppliers to demonstrate actual interoperability with each other before giving them the green tick of approval. That way each hospital, GP surgery or NHS Trust can update its own computers in its own time, training staff and managing the transitions as they go, while still ensuring that the end result is a broader system that works. That is how the Internet was created, so we know that we can produce a planet-wide IT system like that.