16(1)A supplementary charge under this Schedule on a supply within paragraph 2—U.K.
(a)is a liability of the supplier (subject to sub-paragraph (3)), and
(b)becomes due on the date of the VAT change (rather than at the time of supply).
(2)A supplementary charge under this Schedule on a supply consisting of the grant of a right to goods or services within paragraph 3—
(a)is a liability of the grantor (subject to sub-paragraph (3)), and
(b)becomes due on the first occasion on or after the date of the VAT change on which the right is exercised (rather than at the time the right is granted).
(3)If, on the date on which the supplementary charge becomes due, the person who would be liable to pay the charge under sub-paragraph (1) or (2)—
(a)is not a taxable person, but
(b)is treated as a member of a group under sections 43A to 43D of VATA 1994,
the supplementary charge is a liability of the representative member of the group.