(1) A bill is payable on demand -
(a) Which is expressed to be payable on demand, or at sight, or on presentation; or
(b) In which no time for payment was expressed.
(2) Where a bill is accepted or indorsed when it is overdue, it shall, as regards the acceptor who so accepts, or any indorser who so indorses it, be deemed a bill payable on demand.