56.—(1) Where a complaint is recorded under regulation 13(4) (initial handling and recording of complaints), the relevant appropriate authority shall subject to paragraphs (2) to (4), supply the complainant with a written notification setting out a record of that complaint.
(2) A notification supplied under this regulation may keep anonymous the identity of the complainant or of any other person.
(3) A relevant appropriate authority may decide not to supply the complainant with a notification under this regulation if it is of the opinion that to do so—
(a)might prejudice any criminal investigation or pending proceedings, or
(b)would otherwise be contrary to the public interest.
(4) Where a relevant appropriate authority decides not to supply such a notification, it shall keep that decision under regular review.