2. Section 17 shall have effect in relation to any of the articles or substances described in Schedule 1 to this order where any order under that section is made which relates specifically to those articles or substances or to any class of those articles or substances and which appoints in relation to those articles or substances or classes one or more days subsequent to the day or days specified by virtue of paragraph 1 above for the purposes of subsections (2) to (5) of section 16.