71.—(1) Where—

(a) section 70 applies,

(b) a requirement is stated in the notice of termination of the head-tenancy to terminate the sub-tenancy, and

(c) no dispute in relation to the termination of the head-tenancy is referred under Part 6 to the Board, the head-tenant must, within 28 days from the receipt of that notice, comply with that requirement, that is to say, serve a notice of termination in respect of the sub-tenancy on the sub-tenant.

(2) “Head-tenancy”, “head-tenant”, “sub-tenancy” and “sub-tenant” in this section shall be construed in accordance with section 70.