In 2018, UK cannabis law changed via the Misuse of Drugs Regulations 2001, not...

https://dlf-ne.org/what-international-treaties-affect-uk-cannabis-law/

In 2018, UK cannabis law changed via the Misuse of Drugs Regulations 2001, not the Misuse of Drugs Act 1971. This update allows specialist doctors to prescribe cannabis-based medicines like Sativex and Epidyolex under Schedule 2 rules