1. Subject to the provisions of this Schedule, for the purposes of this Order the net annual value of a hereditament shall be the rent for which, one year with another, the hereditament might, in its actual state, be reasonably expected to let from year to year, the probable average annual cost of repairs, insurance and other expenses (if any) necessary to maintain the hereditament in its actual state, and all rates, taxes or public charges (if any), being paid by the tenant.N.I.