Sch 9ZE para 4
A person (“P”) may register under the IOSS scheme if— (a) P makes or intends to make one or more qualifying supplies of goods in the course of a business that P carries on, (b) one of the following applies— (i) P is established in Northern Ireland, (ii) P is established in a country or territory with which the EU has concluded an agreement making provision corresponding or similar to that contained in Council Directive 2010/24/EU or Regulation (EU) No 904/2010, or (iii) P is represented by an IOSS representative established in Northern Ireland (see Part 5), (c) P is not identified under any provision of the law of a member State which implements Section 4 of Chapter 6 of Title XII of the VAT Directive, and (d) P is not barred from registering by— (i) the second paragraph of Article 369l(3) of the VAT Directive, or (ii) any provision of the Implementing Regulation.