for paragraph (1) substitute—

“(1)

This regulation applies where paragraph F1(1) of Schedule 1 imposes a requirement in relation to—

(a)

the creation of a new dwelling by building work; or

(b)

an existing dwelling which undergoes building work for the provision or extension of any fixed building system for mechanical ventilation.

(1A)

Paragraph (1)(b) excludes building work to which Schedule 4 applies.”;