I've watched this - it was OK.
I haven't read the book but I think the script is poor & let the great cast and cinematography down.
And the whole deep dark secret of "Mum was once a pole dancer in the most loving and nice club in the world & lives in utter shame about it even though at the time it was the best thing that could have happened to her" is abysmal. Also she was so adored, loved and cherised by all who ever knew her, while seeming to be a perfectly ordinary, fairly unremarkabale person, was a very weak plot device that the rest of the plot over relied on. I was really expecting some big reveal/twist about that character, and it never came.
They were clearly very well off but no one seemed to work - Megan never did a minutes work the whole time though she constantly used work as a cover.
It did come together a bit more at the end, but ultimately this gets an "overrated & underwhelming" from me.
I guessed the cuplrit very early on - shame they got caught really. So from that aspect it lacked suspense. I couldn't figure out where Barbie & Ken came from?
I did like the ending and how M came to be back where she started - keeping a big secret!