10. Notwithstanding Article 3 of the principal Order, a person who is the holder of a licence to drive motor vehicles granted under Part II of that Order and coming into force on or after the day appointed under Article 1(2) of this Order for the coming into operation of Articles 3 to 6 of this Order and is also the holder of—
(a)a licence under Article 70 of the principal Order to drive public service vehicles of any class, or
(b)a licence under Article 71 of the principal Order to drive heavy goods vehicles of any class,
may drive, or be caused or permitted to drive, a public service vehicle or (as the case may be) a heavy goods vehicle of that class notwithstanding that his licence under Part II of the principal Order does not authorise him to drive such a vehicle.