13A person who at the commencement of section 1A of the Criminal Justice Act 1982 is detained in a detention centre or youth custody centre by virtue of a custodial order—
(a)under section 71AA of the M1 Army Act 1955, section 71AA of the M2 Air Force Act 1955 or section 43AA of the Naval Discipline Act 1957; or
(b)under paragraph 10 of Schedule 5A to the M3 Army Act 1955, Schedule 5A to the Air Force Act 1955 or Schedule 4A to the Naval Discipline Act 1957,
shall be detained in such young offender institution as the Secretary of State may direct, and any enactment applying to persons detained in young offender institutions shall apply to a person so detained under this paragraph.