EV drivers using medical cannabis have a legal defence against the 2mcg/L THC...

https://bizzmarkblog.com/the-motorists-guide-to-medical-cannabis-dvla-rules-section-5a-and-staying-legal/

EV drivers using medical cannabis have a legal defence against the 2mcg/L THC limit, but fitness to drive is paramount. Legality doesn't replace responsibility; impairment is still a liability