Sub-s.(2) of sec.464 provides that if the court of appeal,confirmation or revision is of opinion that failure of justice has in fact been occasioned,it may -- (a) in the case of an omission to frame a charge,order that a charge be framed and that the trial be recommended from the point immediately after the framing of the charge; (b) in case of an error,omission or irregularity in the charge,direct a new trial to be had upon a charge framed in whatever manner it thinks fit