11.—(1) This regulation applies to any buildings with a total useful floor area over 1000 m2 which are occupied by public authorities and by institutions providing public services to a large number of persons and are therefore frequently visited by those persons.
(2) On or after 30th December 2008 the occupier of any building to which this regulation applies shall—
(a)display at all times a valid display energy certificate in a prominent place clearly visible to the public; and
(b)have in his possession or control at all times a valid advisory report.
(3) A display energy certificate is valid for a period of 12 months beginning on the nominated date.
(4) An advisory report is valid for a period of 7 years beginning on the date it is issued.