13.—(1) Where the proper officer is satisfied that a petition is valid, the proper officer shall, within the notice period, notify the National Assembly for Wales and either the petition organiser or where the petition has been amalgamated in accordance with regulation 8(3) the petition organiser of each of the constituent petitions—
(a)of the proper officer’s conclusion; and
(b)that a referendum will be held.
(2) In a case to which paragraph (1) applies, the authority shall publish in at least one newspaper circulating in its area a notice which contains a statement—
(a)that a valid petition has been received;
(b)of the constitutional change sought or, as the case may be, treated as sought, by the petition;
(c)of the petition date;
(d)that the petition is available at the authority’s principal office for inspection by members of the public at all reasonable times and free of charge;
(e)of the address of the authority’s principal office; and
(f)that a referendum will be held.