42   Exclusion of mistake of fact defence

(1)  This clause applies if a provision of this Part states that a person does not have the benefit of the mistake of fact defence for an offence.

(2)  It is not a defence to the offence for the person to prove that, at or before the time of the act or omission constituting the offence, the person was under a mistaken but honest and reasonable belief about facts which, had they existed, would have meant that the act or omission would not have constituted an offence.