Main rules: temporary removals in the course of delivery within in the UK
Section 7 VAT Act 1994
7(8) For the purposes of the preceding provisions of this section, where goods, in the course of their removal from a place in the United Kingdom to another place in the United Kingdom, leave and re-enter the United Kingdom the removal shall not be treated as a removal from or to the United Kingdom.
Section 7(8) provides for the place of supply to be unaffected if goods temporarily leave the UK whilst being delivered from one location to another within the UK. This might arise if goods were, say, transported from Belfast, via the Republic of Ireland, to London.