(1) An appeal to the Supreme Court shall lie with the leave of the Tribunal; and such leave shall not be granted unless it is certified by the Tribunal that a point of law of general public importance is involved in the decision, or it appears to the Supreme Court that the point is one which ought to be considered by that Court.
     (2) An application to the Tribunal for leave to appeal to the Supreme Court shall be made within a period of thirty days beginning with the date of the decision of the Tribunal and an application to the Supreme Court for leave shall be made within a period of thirty days beginning with the date on which the application for leave is refused by the Tribunal.
     (3) An appeal shall be treated as pending until any application for leave to appeal is disposed of and if leave to appeal is granted, until the appeal is disposed of; and an application for leave to appeal shall be treated as disposed of at the expiration of the time within which it might have been made, but it is not made within that time.