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

https://hectorzfzj813.image-perth.org/can-the-home-secretary-change-cannabis-classification-without-parliament

In 2018, the UK updated the Misuse of Drugs Regulations 2001—not the 1971 Act—to allow specialist doctors to prescribe cannabis-based medicines like Sativex and Epidyolex under Schedule 2. Recreational cannabis remains a Class B drug