That was it, you didn’t miss anything. Which I love, because they were just talking like normal people about a story they both already know, and more importantly, know they both already know, so they can reference it by shortcut instead of awkwardly telling the whole thing again just to clumsily convey exposition to the audience.
We can assume that at some point, most likely quite soon after their reunion, Alice would have wanted to know how Vera found her address to even send Frank. And Vera would have told her that she went to a bookshop, found one of Alice’s books, called up the publisher, and got her address. And that would have been that.
And then in this scene decades later, Vera tells her that she didn’t just go to a bookshop, she went to 23. 23! So of course Alice, the big softie, is moved by that.