@MaidOfAle
I'd like to introduce you to a piece of legislation called Data Protection Act 2018 and something called the common law expectation of privacy. These systems not talking to each other is often because key data stores are locked down very tightly to keep the data on them safe. I don't want them all joined up, thanks. My dentist doesn't need to know about my gynecological history.
May I introduce you to password protection and different levels of security. There's no problem at all in technological solutions to "lock down" certain areas of data for specific grades/levels of worker. It's been pretty common place for a few decades. Just needs setting up properly with user data permissions. I don't think anyone has ever suggested that "anyone" with access to "any" NHS data should have access to "all" NHS data. Gynae data would be locked down to Gynae staff (and maybe your GP). Dental data would be locked down to your dental practice staff (and maybe your GP) but anyway dentists are different because they're not usually part of the NHS - they're private businesses providing (sometimes) NHS services so need a different approach, as do opticians, pharmacies audiologists etc.
But generic blood tests whether taken in the GP surgery, hospital or clinic should be available pretty widely across the NHS to your GP surgery and at least your local hospital, same with x-rays, scans, etc!
At the moment, the amount of waste and duplication is criminal where, say, a GP surgery insists on it's own blood test because it can't see the blood test you had done last week in the hospital. Not helped by the hospital consultant telling you to ask your GP for, say, a mineral supplement due to say, iron deficiency, but they don't write to your GP to tell them that, don't share the blood test result, so you have to contact the GP yourself to tell them what the consultant said and their response is always that they need their own blood test before they can issue a prescription for it!
My OH, when first diagnosed with cancer, had a full body x-ray, CT scan, MRI scan, and bone marrow sample in our local hospital, along with a full suite of blood tests. Once diagnosed, he was referred to a specialist hospital in the next city (same NHS trust) and we had a pointless consultation with the specialist because he had no results - just an A4 "referral" letter. He immediately ordered all those tests to be done again because his hospital system didn't "talk" to our nearest hospital so he couldn't get access to the original tests. What was even more stupid was that he said the tests could be done at the same local hospital we had them done first time, but that with the request coming from him and his hospital, they'd send the results to him in a different format that he could access! Doh!!