I actually thought the Dr Hansen doing the cross examining was very average.
She tried to catch him out on several occasions but Mr Blewiit was cool and collected I thought, he got flustered a couple of times but managed to regain his composure.
She though confused documents and lost her train of thought as well as what documents she was referring to a couple of times. As you say Han being she was trying to discredit Blewitt's relevance and credibility, she did not do well at all.
Much of her argument was that Wilson will disagree with what what Mr Blewitt has said. Well that we would expect anyway, so was not much of a credibility statement at all.
I think Mr Blewitt did let himself down at one pont when he said one of the statements he had signed to the Victorian Police he did not actually write himself, and he did not read thoroughly...he apologised and said he did not intend to mislead, and hoped he hadn't perjured himself by the admission in that he glanced through the document but didn't thoroughly read it...that was to do with the amount of cash he had on him when he visited Gillard's house, paid the tradies $7k, then gave the balance of a few grand to Wilson, but the cross examining Dr Hansen did not capitalise on that at all...he was saved a bit by the other guy with the name I can't recall...and of course Dr Hansen suggested the meeting did not happen at all!!
I reckon I can see some Gillard protection creeping in to the argument already as well...