This is surely unlawful discrimination per EA2010? If it isn’t, can someone explain why it isn’t?

it's "not" because it'll be decided by a rigged court that it's not even if it breaks the word of the law, the courts have shown time and time again that theyre heavily biased against trans people, especially when it comes to the equalities act see Roz Adams v ERCC and Forstater v CGD