so not understand why the hospital & GP surgery are not linked & collaborating.
Sadly, despite reassurances over the years, the IT within the NHS is still not particularly stable and trustworthy. Hospitals know this, even if they don't publicly say so and Hospital Trusts don't "trust" sharing their data.
I live in Bucks, had major surgery in Oxford in 2020 and have had 7 Consultant or Specialists helping me since, some in Bucks, some in Oxford. Neither Trust can see correspondence from the other; reports sent to my GP go on my records as inert documents, allegedly not readable by me from my medical digitised records and allegedly only visible to my GP within the surgery. Some reports, such as Hospital discharge letters are compiled from digitally accumulated data and, frankly, are worthless; my last was a wonder of mythology with duplications and repetitions extracted from duplicated data entries.
Just this week, I asked my GP Reception a question about a forthcoming D appointment for feet checks, the Practice internal messaging system managed to convert that into an appointment with the Nurse at 7pm (the Practice closes at 6pm) which was notified to me through the Patient Access app for repeat prescriptions, even though that app does not allow setting up appointments with my Practice. No harm done, but there is a clear "glitch" between the app and the Practice, reflecting that yet another bit of the IT doesn't quite work as intended.
Whether the overarching NHS IT will ever get to a stable state and user friendly is, to my mind, questionable. But abandoning it and starting afresh seems unthinkable (although I know another Public Dept did just that, took the hit and paid a 2nd time for a system they now seem happy with).