6.—(1) Where the investigation procedure is required by virtue of article 5(5) or 5(10), the investigating authority must—
(a)identify any service provider or authority which has or had responsibility for the exercise of the function or functions to which the subject matter of the complaint relates;
(b)notify any such service provider or authority of the complaint; and
(c)request such information or assistance from that service provider or authority as the investigating authority considers necessary to enable it to investigate and determine the complaint.
(2) A service provider or authority which receives a request for information or assistance in accordance with paragraph (1)(c) must comply with the request unless it considers that to do so would—
(a)be incompatible with any duty of the service provider or authority; or
(b)unduly prejudice the exercise of any function of the service provider or authority.
(3) If a service provider or authority refuses to comply with a request for information or assistance as mentioned in paragraph (1)(c), it must provide the investigating authority with its reasons for refusing to do so in writing.
(4) Where paragraph (1) applies the investigating authority must, within the timescale provided for in paragraph (5), write to the person aggrieved with the determination of the complaint, setting out the matters mentioned in article 8(1) so far as they are applicable to the complaint.
(5) The timescale is 20 working days, beginning with—
(a)where the investigation procedure is required by virtue of article 5(5), the day on which the complaint was received; or
(b)where the investigation procedure is required by virtue of article 5(10), the day on which a request as mentioned in article 5(6) was received or, as the case may be, agreement was reached under article 5(9).
(6) In addition to complying with paragraph (4), the investigating authority must—
(a)consider whether there are other means of communication which might assist the person aggrieved in understanding the information mentioned in that paragraph; and
(b)if it considers that there are such means of communication, communicate the information by those means, so far as it is reasonably practicable to do so.