(1) The Revenue Commissioners may extend the operation of a licence under this Act for the appropriate period where, before the expiration of a certificate of personal fitness issued -

(a) to the holder of the licence, or

(b) in case the holder of the licence is a body corporate, to any relevant officer of the body corporate,

under section 4, 5 or 5A, and by reason, in part, of which the holder of the licence was issued the licence, the holder of the licence or the relevant officer, as the case may be, makes an application under that section for a new certificate of personal fitness and a new certificate of personal fitness is not issued or is not likely to be issued earlier than 7 days before the day on which the licence would, but for the exercise of the power conferred by this subsection, expire.