I bought my copy of NHJ from A&R in Melbourne, for what that's worth.

NHJ! (HA): For what it's worth, I'm pretty certain there is no conspiracy at a book-distributor level to not stock Margo's book. Instead, what people are finding is the result of sales far outstripping expectations very quickly. As a rule, booksellers sell books because of the profit margin, and not many would bother cutting profits for the sake of some political point in full knowledge that other shops will just say, 'Thankyou very much'. If individual booksellers here and there choose not to stock the book for their own quixotic political reasons that is another thing, but not of much concern to our democracy. There might be a fine line between a healthy nose for problems in our democracy and paranoia. I might be wrong.

Still, Angus and Robinson's reply to Cheryl Weisenberg might be worth noting, but I suspect it will confirm the above. See also comments by Peter Hackney, Troy Rollo, Phil Edwards and Bill Gregor.