Section 14 of the Principal Act is amended by inserting the following after subsection (2):
"(2A) Where an authorisation has issued to any person in accordance with subsection (1) and that person fails to issue a credit note in accordance with section 17(3) (b) in respect of any supply where the consideration as stated in the invoice issued by that person for that supply is reduced or a discount is allowed, then, at the time when a credit note should have issued in accordance with section 17(7) -
(a) such tax as is attributable to the reduction or discount shall be treated as being excluded from the application of subsection (1), and
(b) that person shall be liable for that tax as if it were tax due in accordance with section 19 at that time.".