4.—The definition of the expression “registration book”contained in section 2 of the Principal Act is hereby amended by the insertion therein of the words “or a copy of the registration particulars of such vehicle issued by the authority by which such vehicle was licensed under the Roads Act, 1920”after the words “the Roads Act, 1920” and the Principal Act and this Act shall be construed and have effect with due regard to the extension of the said expression effected by said amendment.