I am not a lawyer and I'm not a medical professional, so my knowledge of this is not expert. However, as far as I understand, parental consent with child assent is the normal procedure for medical treatment in children.
So Jolyon's wish to make this treatment available with only informed consent from the parents and assent from the child (who is deemed unable to give fully informed consent) would be in line with current arrangements for a child who does not have the maturity to give fully informed consent for other treatments.
If this treatment is viewed as a 'normal' or 'standard' medical treatment, is there a possibility that Jolyon's case could succeed?
The Tavistock procedure of requiring informed consent from the child themselves is highly unusual. I can help wondering whether this is because a surprisingly high number of parents disagree with the proposed treatment.
I thought they required informed consent from both the child and the parent(s). The Tavistock might have been trying to keep the Munchausen by proxy sufferers, homophobes and paedophiles at bay with the requirement of informed consent from the child.
With children now deemed unable to consent, we would need more vigilance from the medical professionals to prevent such parents from inflicting irreversible damage on their children.