(1) Section 20 of the Principal Act is hereby amended by -
(a) the substitution in subsection (1) for "18(1)(b) and (c) " of "18(1)(a), (b) and (c) ", and
(b) the substitution in subsection (4) for "Self-employment contributions payable" of "Other than in the case of such class or classes of self-employed contributors as may be prescribed, self-employment contributions payable".
(2) Section 29 of the Principal Act is hereby amended by the insertion after subsection (6) of the following subsection:
"(7) Regulations shall provide for the return, subject to any conditions, restrictions and deductions specified in the regulations, of so much of any self-employment contribution paid by a self-employed contributor or a voluntary contribution paid under section 23 by a voluntary contributor, who -
(a) had attained the age of 56 years on the 6th day of April, 1988, and
(b) became a self-employed contributor within the meaning of section 17 on or after the 6th day of April, 1988,
as may be