I don’t think that would stand up in court as a defence.
Well as pointed out, 16 is legal.
Of course the lad who I worked with in the RAF many years back who pulled a girl who later turned out to have been 15 (although she was in an over 21 club at the time) ended up having to explain his side of the story to the police after the parents of the girl contacted them over their little angel’s extra-curricular activities.
If he had only gone to ‘The Grapes’ instead he would have been ok as you can pretty much guarantee that no female in their is under 30.