law: 87. What buildings, etc., are to be deemed vacant.
  (1) For the purposes of sections 84 and 85 no building, tenement or land shall be deemed vacant if maintained as a resort or town or country house or be deemed unproductive of rent if let to a tenant who has a continuing right of occupation thereof, whether he is in actual occupation or not.
  (2) The burden of proving all facts entitling any person to claim relief under section 83 or section 84 or section 85 shall be upon him.