by reason of the construction of any tidal work it is reasonably necessary for the Conservancy Authority to incur reasonable costs in temporarily or permanently altering, removing, re-siting, repositioning or reinstating existing moorings or aids to navigation (including navigation marks or lights) owned by the Conservancy Authority, or laying down and removing substituted moorings or buoys, or carrying out dredging operations for any such purpose, not being costs which it would have incurred for any other reason; and

the Conservancy Authority gives to the Harbour Authority not less than 28 days’ notice of its intention to incur such costs, and takes into account any representations which the Harbour Authority may make in response to the notice within 14 days of the receipt of the notice,