After subsection (5) of section 7 (reverse charge on services received from abroad) there shall be inserted the following subsection—

“(6)

The power of the Treasury by order to add to or vary Schedule 3 to this Act shall include power, where any services whose place of supply is determined by an order under section 6(6) above are added to that Schedule, to provide that subsection (1) above shall have effect in relation to those services as if a person belongs in the United Kingdom for the purposes of paragraph (b) of that subsection if, and only if, he is a taxable person.”