‘(1) A magistrates’ court may vary or rescind a sentence or other order imposed or made by it when dealing with an offender if it appears to the court to be in the interests of justice to do so; and it is hereby declared that this power extends to replacing a sentence or order which for any reason appears to be invalid by another which the court has power to impose or make… (2) Where a person is convicted by a magistrates’ court and it subsequently appears to the court that it would be in the interests of justice that the case should be heard again by different justices, the court may…so direct.’