A requirement to do what is necessary to inform designated persons holding office under the Crown concerning matters and things transmitted or in course of transmission by means of postal or F1telepost services provided by the Post Office may be laid on the Post Office for the like purposes and in the like manner as, at the passing of this Act, a requirement may be laid on the Postmaster General to do what is necessary to inform such persons concerning matters and things transmitted or in course of transmission by means of such services provided by him.