3(1)In determining, for the purpose of sections 21 and 22, the amount of the expenses reasonably incurred by the owner in carrying out remedial operations, there shall be deducted any sum which—
(a)is recoverable (or has been recovered) by the owner from the local authority by virtue of an order under section 16(4); and
(b)is referable to expenditure incurred by the owner in consequence of the service of the notice under section 14.
(2)No sum shall be recoverable by the owner under section 21 in respect of expenses incurred by him in carrying out works of reinstatement.