I don't think anyone here is in a position to comment without the facts but (a) if the leading expert witness has changed his evidence that is not a point of procedure - it is stunningly significant; and (b) it is the responsibility of the prosecution to disclose all evidence to the defence, not the witnesses, and it is alleged that the prosecution has had the new evidence for months and did not disclose it - that is a gross dereliction of their duty.
I honestly do not know whether she is guilty of what she has been accused of or not. I have never seen the evidence or heard every word of testimony or argument. Unlike, it would appear, half the people on this site. But I am deeply concerned that the only evidence presented was circumstantial; and events such as this serve to undermine confidence in the judicial system when, on the face of it, someone can be convicted without any actual evidence and the prosecution can be shown to have withheld evidence - if they have withheld evidence once, who is to say that they haven't withheld other evidence that isn't convenient to their case?