It raises the question: what's special about PB treatment for gender dysphoria compared to other treatments a child can consent to? If the Court of Appeal accepts that PBs in most cases lead to treatment by cross-sex hormones, the answer would be quite a lot. Can a child give up all that that entails when, by any sensible measure, they can never really understand what they're giving up? The answer from the appellants would seem to be that what the gender dysphoric child gets from the treatment is so significant, then the question of loss is of less importance
To be clear - I agree with the original judgement but, if I were advising the Tavi team (I am a doctor, not a lawyer, but do a lot of medico-legal work), I would say - how is this different in principle from an abortion? An abortion is permanent, non-life saving (in most cases) and less reversible than PBs. And we know that some women do go on to regret them (I am pro-choice: again, I am not reflecting my own views here)
For the appeal to fail, the AC will need to uphold the original judgement that there is a clear difference in law between PBs and all other treatments, in order to create a rationale for treating PBs in unique way, as regards competency. I think that will be hard. I suspect we will end either in a fudge, where the original judgement is overturned, but with a finding that the Tavi should have a low threshold for going to court before prescribing PBs, and/or with the hot potato being passed to the Supreme Court.