(1) A bill is dishonoured by non-acceptance-

(a) when it is duly presented for acceptance, and such an acceptance as is prescribed by this Act is refused or cannot be obtained; or

(b) when presentment for acceptance is excused and the bill is not accepted.

(2) Subject to the provisions of this Act, when a bill is dishonoured by non-acceptance, an immediate right of recourse against the drawer and endorsers accrues to the holder, and no presentment for payment is necessary.