You can chose your GP based on the software they use and the governance procedures they have in place to handle your data. When you're referred on for elective

You can chose your GP based on the software they use and the governance procedures they have in place to handle your data. When you're referred on for elective care you can chose the hospital based on the same criteria. You don't get much choice over emergency treatment, nor over mental health treatment. I get the impression that people here think that you have one medical record that is available across all the NHS, but that's not correct. You have a bunch of different records in different places and they're not available to each other.