4. An airport operator shall pay compensation in respect of any expenditure reasonably incurred by any person—
(a)for the purpose of carrying out work which is required to be carried out by a direction given under Article 8 in relation to the airport;
(b)in connection with the lawful removal of any apparatus installed in pursuance of an order made under Article 9 in relation to the airport or in connection with so much of any repair, alteration, demolition or removal of any building, structure or erection to which such an order relates as is attributable to the operation of the order.