Medical cannabis is legal, but driving is a separate issue. Stick to the 2µg/L...

https://www.bookmark-suggest.win/think-a-medical-cannabis-script-is-a-get-out-of-jail-card-think-again-you

Medical cannabis is legal, but driving is a separate issue. Stick to the 2µg/L limit and inform the DVLA of your status. A medical defence isn’t a get-out-of-jail-free card; if you’re impaired, you’re liable. Legality never replaces responsibility.