5.—(1) If any part of the works comprising a structure in, over or under a drainage work is constructed otherwise than in accordance with the requirements of this Schedule, the Agency may by notice in writing to the Council require the Council, at the Council’s own expense, to comply with the requirements of this Schedule or (if the Council so elects and the Agency in writing consents, such consent not to be unreasonably withheld) to alter the work to the reasonable satisfaction of the Agency.
(2) Subject to sub-paragraph (3), if within a reasonable period, being not less than 28 days from the date when a notice under sub-paragraph (1) is served on the Council, it has failed to begin taking steps to comply with the requirements of the notice and thereafter to make reasonably expeditious progress towards their implementation, the Agency may execute the works specified in the notice and any expenditure incurred by it in so doing shall be recoverable from the Council.
(3) In the event of any dispute as to whether sub-paragraph (2) is properly applicable to any work in respect of which a notice has been served under that sub-paragraph, or as to the reasonableness of any requirement of such a notice, the Agency shall not, except in emergency, exercise the powers conferred by sub-paragraph (2) until the dispute has been finally determined.