Interesting too see that the paper linked by ItsAllGoingToBeFine refers to the adolescent giving their "informed consent / assent" to blocker treatment.
Assent refers to getting agreement from a patient when they are not able to give informed consent, when their parent/guardian had given their informed consent. (I think this is the more standard procedure when treating children. Gillick usually only comes into play when there is a conflict between what the parents and the child want, or when the child needs to make a decision in the absence of their parents.)
I wonder if this is why Scotland is still prescribing?
The Tavistock made a big deal of only going ahead with blockers if the patient themselves could provide informed consent. This was somewhat undermined by the lawyer for the endocrinology service, who implied that responsibility in the case of regret lay with the child's parents.
Perhaps Scotland has always allowed parental consent + child assent for the prescribing blockers and has therefore sidestepped the issue of Gillick competence entirely.