Where to buy The Guardian and other British newspapers & magazines?

Call me old-fashioned, but I still occasionally like to read a printed newspaper and magazine. Specifically, I'm looking for a place that carries the Saturday/weekend editions of British newspapers, in particular The Guardian. I'm simply addicted to their Saturday 'Review' section, which has lots of book reviews. On that note, does anyone know of a place where one can buy the print editions of the London Review of Books and the New York Review of Books? (In case you are wondering, yes I work in the publishing business...) And is there maybe a magic place where one can find *all of the above* in one place?? Thanks for your help!