4The reference in Part I of this Schedule to the Commissioners of Inland Revenue is a reference to those Commissioners only to the extent that the functions carried out by them or any officer of theirs relate to—
(a)any of the following aspects of social security—
(i)National Insurance contributions;
(ii)statutory sick pay;
(iii)statutory maternity pay; or
(b)the tax treatment of occupational or personal pension schemes.