(1) Section 20 of the Principal Act is hereby amended -
(a) in subsection (1) (inserted by the Act of 1981) by the substitution of "Subject to subsections (1A) and (1B)" for "Subject to subsection (1A)",
(b) by the insertion after subsection (1A) (inserted by the Act of 1991) of the following subsection:
"(1B) The Revenue Commissioners may, where it appears requisite to them to do so for the protection of the revenue, require as a condition for making a refund in accordance with subsection (1) the giving of security of such amount and in such manner and form as they may determine:
Provided that the amount of such security shall not, in any particular case, exceed the amount to be refunded.",
(c) in subsection (3) by the substitution of the following paragraph for paragraph (a):
"(a) The Minister may by order provide that a person who fulfils to the satisfaction of the Revenue Commissioners such conditions as may be specified in the order shall be entitled to be repaid so much, as