Their safeguaridng has this about water polo:
" Where junior males and females train together,
the coach must be aware of the heightened risk
that this may present. To minimise any risk, it
would be best practice to have a chaperone
on poolside whose only duty is to ensure the
safety of the junior players by providing extra
supervision as described in point three above"
UNLESS they are transgirls and girls in which case no heightened risk obviosuly.