Credibility evidence, in relation to a witness or other person, is evidence relevant to the credibility of the witness or person that –

(a) is relevant only because it affects the assessment of the credibility of the witness or person; or

(b) is relevant –

(i) because it affects the assessment of the credibility of the witness or person; and

(ii) for some other purpose for which it is not admissible, or cannot be used, because of a provision of Parts 2 to 6 of Chapter 3 .