2. Notwithstanding section 72(3) of the Children and Young Persons Act (Northern Ireland) 1968 [1968 c.34] , a person who immediately before the appointed day is serving a sentence of training in a Borstal institution shall as from that day be deemed to be serving a sentence of detention for a term of two years in a young offenders centre passed on the date on which he was sentenced to Borstal training.N.I.