13.—(1) Subject to paragraph (3), regulation 12(b)(i) shall not apply in relation to a display energy certificate that is displayed by an occupier of a building at any time before he has been in occupation of the building for 15 months.
(2) Regulation 12(b)(ii) does not apply in relation to a display energy certificate which is displayed by an occupier who entered into occupation of the building before 31st December 2008.
(3) Where on 31st December 2008 the occupier of a building has been in occupation for less than 15 months the operational rating specified for the purposes of regulation 12(b)(i) may be calculated over the period in which the occupier has been in occupation.