409. Amount of rent.

409.     Amount of rent.

On any reference made in pursuance of a statutory review notice1, the arbitrator2 must determine the rent properly payable in respect of the holding3 at the review date4 and accordingly must, with effect from that date, increase or reduce the rent previously payable or direct that it continues unchanged5. For these purposes the rent properly payable in respect of a holding is the rent at which the holding might reasonably be expected to be let on the open market by a willing landlord to a willing tenant6,