A person is not guilty of aiding, abetting or counselling the commission against a child of an offence to which this section applies if he acts for the purpose of—
protecting the child from sexually transmitted infection,
protecting the physical safety of the child,
preventing the child from becoming pregnant, or
promoting the child's emotional well-being by the giving of advice,
and not for the purpose of obtaining sexual gratification or for the purpose of causing or encouraging the activity constituting the offence or the child's participation in it.
This section applies to—
an offence under any of sections 5 to 7 (offences against children under 13);
an offence under section 9 (sexual activity with a child);
an offence under section 13 which would be an offence under section 9 if the offender were aged 18;
an offence under any of sections 16, 25, 30, 34 and 38 (sexual activity) against a person under 16.
This section does not affect any other enactment or any rule of law restricting the circumstances in which a person is guilty of aiding, abetting or counselling an offence under this Part.