Where an offender has before the commencement of sections 1 to 15 above been committed for sentence to the Crown Court under section 37 of the [1980 c. 43.] Magistrates' Courts Act 1980 but has not been dealt with by the Crown Court before the commencement of those sections, he shall be deemed to have been committed for sentence under section 37 of that Act as amended by this Act.

A court to which it falls to determine for the purposes of any enactment how a previous court could or might have dealt with an offender, shall if the offender is under 21 years of age make that determination as if sections 1 to 15 above had been in force when the offender was dealt with by the previous court and the powers conferred by them had accordingly been available to that court when dealing with him instead of the powers which were in fact available to it.