well I have found it from UK amazon though I didnt check where it was shipping from come to think of it... I was going to buy from ebay as I have paypal but my cc is maxed out at the moment. But it sounds the sort of thing you want to reference again later on? So more a buy than a borrow?
I'd agree order from library, then if you feel it's an indispensible reference tool you can always buy it later. I personally think it's useful to be able to refer back to once a year or so, as the kids' abilities to communicate change and develop. But you might not like it.