I'm in Australia and the series has been running for a while. I've also read the book, and happened to like it despite the fact that every character is totally unlikeable.
It isn't a "nice" story, but it really does explore the characters in depth.
The author is an Australian of Greek decent, but as for thinking the sex in the story must be a reflection of Aussie males - that's a a tad unfair, I'm married to an Aussie and have had several Aussie boyfriends, not all of them thought foreplay consisted of, "Do you wanna shag?". The author was interviewed on TV, I quite like him. Incidentally,he is gay (though that really doesn't make any difference).
The "slap" itself has been hotly debated at my dinner table. Would you ever slap someone else's child? A four or five year old? Under what circumstances, if any, is it okay to slap someone else's (or even your own) child? And would you press charges if a relative or friend did it to your child?
They are horrible characters, but the story really does get you thinking.