4B.—(1) Any person who supplies gas through a meter—
(a)which has not been overhauled in accordance with a requirement imposed under regulation 3B(1) above; or
(b)which has not been replaced in accordance with a requirement of a notice published under regulation 4A(2)(b) above;
shall be guilty of an offence and liable on summary conviction to a fine not exceeding level 3 on the standard scale.
(2) Where the commission by any person of an offence under paragraph (1) above is due to the act or default of some other person, that other person shall be guilty of the offence; and a person may be charged with and convicted of the offence by virtue of this paragraph whether or not proceedings are taken against the first-mentioned person.
(3) In any proceedings for an offence under paragraph (1) above it shall be a defence for the person charged to prove that he took all reasonable steps and exercised all due diligence to avoid committing the offence.]