I didn't like the ending much. Is it true to the book? I can't remember her visiting Mark in jail. And I'm not sure what happened to the computer diary-did her husband find it?
As far as I remember, more was made of the son's mental illness in the book.
So, to sum up.....Mark gets manslaughter (on grounds of diminished responsibility), Yvonne gets off but gets six months for perjury, which is suspended. This enables her to visit Mark, and for the producer to invent the conversation which makes the conclusion slightly different to the book, but still ambiguous.
Personally, I don't think Yvonne meant for George to be killed. If she'd wanted some sort of revenge, she could've gone to the police, reported it, and that alone may have been enough to destroy his reputation.
I think Mark was using Yvonne's situation to build the fantasy about himself. He saw himself as some sort of conquering hero, with power to injure or kill. He didn't have the skills to carry his fantasy through effectively enough to ensure he wasn't caught.
I'm still not sure if, after all, Yvonne was using him vicariously to exact revenge on George. The attack was hardly well-planned or discreet, and Yvonne must have had some idea of the implications of both their actions. I think Mark was very lucky to get away with manslaughter.
I was sympathetic to Yvonne until she lied in court, and I don't really get why she felt she had to. The truth would've come out about the relationship anyway, so why perjure herself, and mislead her legal team?