I find Sarah sad. She's that everywoman but for a bad choice here and there who would have had a very nice, happy life and she knows it. She is intelligent enough to see the almost inevitable progression from bad choice to worse choice and so on but has too few trained executive functions to figure the right path.
I think she would do anything to repair her public image, if for no other reason than I believe she loves her daughters deeply. Problem is, she just does not know how. That is a sad state for any human, one guesses - to want to be better and not know how. Eventually all your bad choices rob you of your confidence in making new choices, good or bad, and you start letting events and actions pick you, so to speak. She has that passenger on a train wreck who didn't pay attention to the emergency information look.
Poor woman.
I never have any bad feelings towards Sarah, even with that pathetic money for access thing. I mean, there she is, on tape, taking a briefcase full of money in exchange for getting Andrew to meet with someone and she is saying, in all earnestness, something to the effect that this should not be seen as a reflection on Andrew. At one point she even utters the phrase "...he is lily white. Pure. You understand? " in the most sincere of all tones. And I think she was ... sincere. She really thought she could divorce his character from her actions. That's sad. And it makes you realize how desperate she must have been.
I don't know ... some examples of bad judgement (Diana's Panorama interview, as an example) have clear "bad motives" - that is to say, a motive to cause harm. Sarah's always seem innocent in this regard. I don't think she *meant* to harm Andrew or the BRF. Which is not to say her intentions were good - clearly they were not - but I don't think they were evil or deliberately destructive.