3(1)Compensation under this Schedule shall not be payable for an old improvement specified in any of paragraphs 1 to 15 of Part II of this Schedule unless, before the execution of the improvement, the landlord consented in writing (whether unconditionally or upon terms as to compensation or otherwise agreed between him and the tenant) to the execution of the improvement.
(2)Where the consent was given upon agreed terms as to compensation, compensation payable under the agreement shall be substituted for compensation under this Schedule.