I'm not in the UK. A family member transitioned. They had many, many sessions with a pyschologist before any treatment at all could be started. It was not a matter of turning up and saying that they were a different gender. The parents were initially shocked (major understatement there) but came to accept that their child truly was transgender - yes I understand they tried reasoning, and frankly everything they could think of to convince the child that they were the original gender. They told me they were haunted by the idea of later regrets.
Their child did transition. The child is in a long standing relationship. They have friends. They are doing a post graduate degree. They are happpy. The family pulled together and adopted the new gender, even the grandparents got on board showing an amazingly broad minded side we had never seen before. So far as I know, the young person has not had a single regret a decade later. This is the other side of the story.