(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 is 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.