In this Part of this Act -

(a) "debt" includes any liquidated pecuniary claim;

"statute-barred debt" means a debt in respect of which the period fixed by this Act for the bringing of an action to recover it has expired;

"successor" means - (i) in relation to a mortgagee - his personal representatives and any other person on whom the rights under the mortgage devolve, whether on death or bankruptcy or the disposition of the property or the determination of a limited estate or interest in settled property or otherwise, (ii) in relation to a person liable in respect of a debt - his personal representatives and any other person on whom the liability in respect of the debt devolves, whether on death or bankruptcy or the disposition of the property or the determination of a limited estate or interest in settled property or otherwise;

(b) references to a right of action shall include references to -

(i) a cause of action,