5. The amount by reference to which any increase in the rate of an official pension provided for by this Order is to be calculated shall, in the case of a person who
(a)is entitled to a guaranteed minimum pension on 24th November 1980, and
(b)whose entitlement to that guaranteed minimum pension arises from an employment from which (either directly or by virtue of the payment of a transfer credit under section 38 of the 1975 Act) entitlement to the official pension also arises,
be reduced by an amount equal to the rate of the guaranteed minimum pension unless the Minister for the Civil Service shall, in accordance with the provisions of section 59A of the 1975 Act, otherwise direct.