5.—(1) Subject to paragraph (2), where a fee has been paid at a time—
(a)when, under regulation 3, it was not payable, the fee shall be refunded;
(b)when the Tribunal, if it had been aware of all the circumstances, would have reduced the fee under regulation 4, the amount by which the fee would have been reduced shall be refunded; and
(c)when the Tribunal, if it had been aware of all the circumstances, would have waived the fee under regulation 4, the fee shall be refunded.
(2) No refund shall be made under paragraph (1) unless the appellant applies to the Tribunal in writing within 6 months of paying the fee.
(3) The Tribunal may extend the period of 6 months referred to in paragraph (2) if it considers that there is good reason for an application being made after the end of the period of 6 months.