4.—(1) The appropriate authority must consult such of the consultation bodies as it considers appropriate before giving a screening opinion.
(2) When carrying out any consultation under sub-paragraph (1), the appropriate authority must allow the consultation body a reasonable period within which to respond, and that period must not be less than 28 days from the date of the letter to the consultation body from the appropriate authority or such other period as may be agreed between the consultation body and the appropriate authority.