15Where in consequence of listed building consent being revoked or modified by an order under Part II of this Schedule, compensation is payable in respect of expenditure incurred in carrying out any works to the building in respect of which the consent was granted, then if a listed building purchase notice is served in respect of an interest in the land, any compensation payable in respect of the acquisition of that interest in pursuance of the purchase notice shall be reduced by an amount equal to the value of the works in respect of which compensation is payable by virtue of paragraph 10 above.