(1) The first actuarial funding certificate shall have an effective date -

(a) in the case of a relevant scheme which commenced before 1 January 1991, not later than 1 January 1994, and

(b) in the case of a relevant scheme which commenced on or after 1 January 1991, not later than 3½ years after the commencement of the scheme, and

(ba) in the case of a scheme to which this Part applies by virtue of the amendment effected by section 31(a) of the Social Welfare and Pensions Act 2005, not later than 1 April 2007, and

(bb) in the case of a relevant scheme which commenced after 22 September 2005, not later than 3 years after the commencement of the scheme, and

(c) in the case of a scheme to which this Part applies by virtue of the amendment effected by section 32(a) of the Social Welfare and Pensions Act 2005, not later than 1 January 2007, and

(d) in the case of a scheme which has been excluded, in whole or in part, from the application of this Part by virtue of regulations made under section 52 and which is no longer so excluded, not later than 6 months after the date on which the exclusion ceases to apply, and