5. Articles 3 and 4 do not apply—
(a)in relation to any sentence imposed before the day on which this Order comes into force,
(b)in relation to an offender who was aged under 18 at the time the sentence for the relevant violent or sexual offence was imposed, or
(c)in relation to a sentence imposed under section 236A of the 2003 Act (special custodial sentence for offenders of particular concern).