(1)Nothing in this Part affects any other enactment, or any rule of law, by virtue of which the assignation of a claim is of no effect.
(2)But such an enactment or rule of law does not apply to an assignation if the grounds on which the assignation would be of no effect by virtue of that enactment or rule are grounds which this Part provides do not make the assignation of no effect.
(3)The assignation, in whole or in part, of a claim is of no effect if and in so far as, before the assignation document in respect of the claim was granted—
(a)the debtor and the holder of the claim had agreed that the claim was not to be so assigned, or
(b)the person whose unilateral undertaking gives rise to the claim had stated that the claim was not to be so assigned.
(4)For the purposes of subsection (3)(a), it does not matter whether the holder of the claim became the holder of the claim after the agreement was made.
(5)Nothing in subsection (3) affects the operation of any other enactment concerning the effect of an agreement or statement such as is mentioned in that subsection.