In the UK, medical cannabis prescriptions start with a specialist...

https://averyssuperthoughts.theburnward.com/can-i-ask-my-nhs-doctor-about-medical-cannabis-even-if-prescriptions-are-rare

In the UK, medical cannabis prescriptions start with a specialist assessment—usually through private clinics, as NHS prescriptions are rare. If approved, you’ll get your medicine from a regulated pharmacy to ensure quality and safety