Yes, that was the one.
As with US content, I have no idea about the organisation is organising the seminar and what their motivation is. I think it was linked on a thread about the Mermaids people attending some US conference, with various people advocating early transtion for children. It provided a useful counterbalance. As with many things, what seems like a good idea in your teens, may well coime back and bite you. Medical transition being a particularly big thing to go on a regret later.
It is important to note that even long term transexuals who do not appear to regret their decision, often warn that it is not a decision to be taken lightly and so openly oppose self-ID.
There is so much that we simply do not know. I wish money was being put into sensible, open-minded and peer reviewavble research. Perhaps the Big Lottery Fund might find themselves with £500,000 that they could reallocate.