There is no "official list" of conditions for medical cannabis in the UK....

https://wiki-wire.win/index.php/Why_Do_Some_UK_Patients_End_Up_Using_Private_Clinics_for_Medical_Cannabis%3F

There is no "official list" of conditions for medical cannabis in the UK. Instead, eligibility depends on a specialist consultant’s clinical review. You generally need to show that other standard treatments haven’t worked for your symptoms first