Exemption for defence authorities narrows notification applicability, excluding most Ministry of Defence offices except listed controllers. Inserts a proviso excluding authorities under the Ministry of Defence, other than those listed in Annexure A, from the applicability of the notification insofar as it concerns persons specified under clause (a) of sub section (1) of section 51 of the Act, with effect from the stated effective date; Annexure A lists Principals/Controllers of Defence Accounts and their code numbers, identifying which defence offices remain subject to the notification.