4Where, in the case of a determination to which this Schedule applies.—
(a)planning permission for the carrying out of the operations, or for the institution or continuance of the use. to which the determination relates is modified by an order made under section twenty-seven of this Act, or
(b)an order is made under section twenty-eight of this Act requiring the alteration of any buildings or works erected or constructed in the carrying out of those operations, or imposing conditions on the continuance of that use, as the case may be, or
(c)part (but not the whole) of the land to which the determination relates is compulsorily acquired under this or any other Act,
the Minister shall, on application made to him in accordance with regulations under this Act, vary the determination, and amend, discharge or release any covenants or charges made or given in respect thereof, so far as may be just in consequence of the order or acquisition, as the case may be.