13.—(1) Where the proper officer is satisfied that a petition is valid, he or she shall, within the notice period, notify the petition organiser—
(a)of his or her conclusion; and
(b)that a referendum will be held.
(2) In a case to which paragraph (1) applies, the authority shall, as soon as reasonably practicable after the paragraph (1) requirement has been met, publish a notice which contains a statement—
(a)that a valid petition has been received;
(b)of the constitutional change 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.