71.—(1) Where an application for a grant has been approved by the Executive, paragraph (2) applies in any case where—
(a)the eligible works are not completed to the satisfaction of the Executive within the period specified under paragraph (2) of Article 56, or such extended period as they may allow under paragraph (3) of that Article; or
(b)the Executive ascertains that the aggregate of the cost of completing the eligible works and the costs incurred with respect to preliminary or ancillary services and charges, is or is likely to be lower than the estimated expense; or
(c)the Executive ascertains that without its knowledge the eligible works were started before the application was approved and the application was neither—
(i)one which the Executive was required to approve by virtue of Article 50 in a case where completion of the relevant works was necessary to comply with a notice under Article 41 of the Order of 1981 (repair notice requiring works to render premises fit for human habitation); nor
(ii)one which the Executive was required to approve by virtue of Article 51.
(2) Where this paragraph applies, the Executive may—
(a)refuse to pay the grant or any further instalment of grant which remains to be paid; or
(b)make a reduction in the grant which, in a case falling within paragraph (1)(b), is to be a reduction proportionate to the reduction in the estimated expenses;
and may demand repayment by the applicant forthwith, in whole or part, of the grant or any instalment of the grant paid, together with interest at such reasonable rate as the Executive may determine from the date of payment until repayment.