120.—(1) Where a condition to which an amusement permit is subject is contravened or a requirement imposed under Article 118 is contravened the holder of the amusement permit shall be guilty of an offence.
(2) In any proceedings for an offence under paragraph (1), it shall be a defence for the holder of the amusement permit to prove—
(a)that the contravention occurred without his knowledge, and
(b)that he exercised all such care as was reasonable in the circumstances to secure that the provisions in question would not be contravened.