Section 42 Agreements as to compensation for old improvements specified in Part III of Second or Third Schedule.

where an agreement in writing entered into before the first day of January, nineteen hundred and twenty-one, secures to the tenant for an old improvement specified in Part III of the Second Schedule to this Act or in Part III of the Third Schedule thereto fair and reasonable compensation, having regard to the circumstances existing at the time of the making of the agreement, the compensation so secured shall as respects that improvement be substituted for compensation under this Act.