Ok then let's try another scenario. William Joyce, after being captured was returned to the UK after WW2 and was given a trial under English law, was found guilty of treason and sentenced to be hanged. He appealed, which was his right, and the Appeal upheld the sentence which was duly carried out. At least he had been tried.
This girl has not been tried, just summarily stripped of her citizenship, but should be given the opportunity, as Joyce was, of stating her case under English Law, which I'm sure you would expect if you were in her position.