In 2018, the UK amended the Misuse of Drugs Regulations 2001—not the 1971...

https://wiki-tonic.win/index.php/Is_It_Illegal_to_Import_Cannabis_into_the_UK_Even_for_Personal_Use%3F

In 2018, the UK amended the Misuse of Drugs Regulations 2001—not the 1971 Act—to allow specialist doctors to prescribe cannabis-based medicines like Sativex and Epidyolex. Cannabis remains a Class B drug, with recreational use still illegal