4.—(1) In the case of a person to whom Rule 2 applies, who did not on the 1st January, 1946, or at any time thereafter have pension rights in a pension scheme associated with his former employment, the period of his former employment shall, subject to the following provisions of this rule, be treated for the purposes of the Superannuation Acts as if it had been continuous service in an unestablished capacity ending immediately before the date on which the said person became a civil servant.
(2) The foregoing provisions of this rule shall not apply to any person unless, not later than the 5th July, 1949, he pays into the Exchequer a sum equal to two per cent. of his former emoluments multiplied by one half of the number of years of the period of his former employment:
(a) a person may, with the consent of the Treasury, be permitted to pay the said sum by equal instalments to be deducted from his emoluments as a civil servant throughout the period of his service as a civil servant;
(b) where a person dies or ceases to be employed as a civil servant before he attains Civil Service retiring age and no allowance or gratuity under the Superannuation Acts is payable in his case, an amount equal to the sum so paid (or, if he has been permitted to pay by instalments, an amount equal to the aggregate of the instalments he has paid) shall be repaid out of the Exchequer; and
(c) where a person who has been permitted to pay by instalments dies or ceases to be employed as a civil servant before he attains Civil Service retiring age, and an allowance or gratuity under the Superannuation Acts is payable in his case, an amount equal to the aggregate of the instalments remaining unpaid shall be recoverable by deduction from that allowance or gratuity, either in one sum or in such instalments as the Treasury may determine.
(3) For the purposes of the foregoing paragraphs of this rule, any person the period of whose former employment exceeds twenty years shall be treated as if that period were twenty years.
(4) Where a person to whom this rule applies had at some time before the 1st January, 1946, pension rights in a pension scheme associated with his former employment, there shall for the purposes of this rule be excluded from the period of his former employment any part of that period which was pensionable employment for the purposes of that pension scheme:
(5) For the purposes of this rule, if the period of a person's former employment was not an exact number of years, any part of a year which is less than six months shall be ignored and any part which is six months or more shall be treated as one year.