7A court to which it falls after the commencement of this Act to determine for the purposes of any enactment how a previous court could or might have dealt with an offender shall in the case of an offender aged under 18 make that determination—
(a)as if sections 100 to 107 of this Act (detention and training orders) and section 96 of this Act (detention in a young offender institution available only if offender is at least 18) had been in force; and
(b)as if sections 1 to 4 of the [1994 c. 33.] Criminal Justice and Public Order Act 1994 (secure training orders, repealed by the [1998 c. 37.] Crime and Disorder Act 1998) had not been in force.