Again, in the most general of terms, where it is an offence to do X but there is a statutory defence of absence of intention to do Y, and where the defendant has denied doing X, evidence about X might also be relevant to Y.
So, where a sharebroker facilitates the transfer of legal ownership of shares, when in fact the beneficial ownership does not change, he is deemed to have committed the offence of creating a false appearance of active trading in those shares, but he has a defence if he proves he did not have the purpose of creating that appearance (see para [5-8] of Braysich for the relevant legislation). The circumstances in which he transferred the shares may be relevant to whether he had the proscribed purpose. When he denies knowing that the beneficial ownership did not change, evidence of his good character will be relevant to that, and it will also be relevant to whether he had the proscribed purpose.
Obvious though this may be in retrospect, the Court split 3-2 on whether the defence case was sufficient to raise the defence of absence of the proscribed purpose. Heydon J agreed with Bell J and added  that all the defendant had done at trial was to point to evidence which, although not inconsistent with the absence of purpose did not actually support absence of purpose. Bell J  considered that there was no evidence of any purpose other than the impugned purpose. Although the defendant had acted for fees for valued clients, that could not, without more, establish that it was probable that he did not have that purpose. The majority, French CJ, Crennan and Kiefel JJ, held that on the view most favourable to the defendant the jury could well have asked whether it was really likely that an honest man who is acting on instructions from reputable people, who he has no reason to believe have a dishonest purpose, would himself have that dishonest purpose when he is aware of the business rules and the law , and that therefore the defence should have been put to the jury.
There was no disagreement about what the law is on whether a defence should be put to the jury. The relevant question in this case was :
Why the big difference between the majority and the minority? I suspect the minority have taken the stance that unless an individual item of evidence gives rise to a probability of innocence greater than 0.5, it does not support the defence. This approach allows the minority to say that evidence that is merely consistent with absence of purpose does not support absence of purpose. The correct way to look at this, as Bayesian logicians tell us, is to ask what is the probability of getting the evidence, assuming the defendant is innocent, compared to the probability of getting it, assuming that he is guilty. Comparison of those probabilities, assessed intuitively, would indicate that each of the items of evidence relied on by the defendant was more likely to exist if he was innocent than if he was guilty, so they individually and in combination support the defence.