18.—(1) Subject to paragraphs (2) and (3), on any holding where there is a pig or poultry enterprise or both the total livestock manure storage capacity on the holding shall be sufficient for at least 26 weeks storage.
(2) On any holding with less than 10 breeding sow places or 150 finishing pig places and any holding with less than 500 poultry places the total livestock manure storage capacity on the holding shall be sufficient for at least 22 weeks storage.
(3) On any holding where there is—
(a)a pig enterprise;
(b)a poultry enterprise; or
(c)both a pig and poultry enterprise,
(4) in addition to another livestock enterprise the livestock manure storage capacity on the holding shall be sufficient for at least 26 weeks storage for the pig or poultry enterprise and at least 22 weeks for the other livestock enterprise.