Another fine Tessa Hadley story in the New Yorker

As I've noted in previous post, I'm getting to appreciate Tessa Hadley, the New Yorker's current English short story go-to girl, a lot more w/ each story of hers I read; some of the first that I came across seemed unduly fussy and almost, if this makes any sense, too self-consciously British, as if every chance she could she used a purely English locution (council houses, in hospital, firsts in maths, and so on). Whether I'm more tolerant of those locutions now or she does so less or I was wrong in my judgment, I'm not sure - but her recent stories have been very strong by any measure. The one in last week's New Yorker, One Saturday Morning, is one of the many great stories in the wake of James Joyce that have a true narrative arc but are left open and evocative at the conclusion - a form that was once startling and now is a standard model for much short fiction. Hadley writes often and well about young people - in this case a girl of I think about 10, set in the 1960s - so it would seem that the story is in part autobiographical, at least in mood - whether the facts of the story ever happened to Hadley or in fact to anyone is immaterial. Simply, the story is of a young girl left at home on a Sat. morning while parents out shopping for a dinner party - parents are somewhat bohemian intellectual and house is much like that of any young professor of the era - an older house in an  unfashionable (and now highly fashionable) neighborhood done up creatively, in this case by the mother; while she's alone (brother outside playing cricket) an old family friend shows up at the door; she invites him in and as he waits for her parents to return she has some kind of longing to impress him - perhaps a sexual stirring. When parents return, she eavesdrops and learns his wife has died; he returns for the evening party and she witnesses from the shadows his bumbling attempt to caress her mother and the mother's rebuff. So, in a sense, nothing happens: we had expected the visitor might abuse her, or something dramatic another writer might employ. Hadley is much more subtle, and w/out really describing the feelings directly we understand that the young girl is getting her first sensation of the stirrings of adult life: death, infidelity, flirtation, competition. There are other side elements in the story - her brother's athleticism, father playing ping pong aggressively, a jokey letter of sexual innuendo that the girl exchanges with a friend and that she fears the piano teacher may have read, and it all builds to a mood of mystery and longing. Interestingly, Hadley writes about children but not at all like a child - her writing is highly formal, literate, full of complex and surprising word choices - remind of Updike at times - not at all the way a child would phrase or think - but she also avoids any direct hint that the narrator is the child as adult looking back - all of which gives the story a strange sense of isolation in time and space. Who's telling the story, and how does she have such deep and direct knowledge of the young girl's consciousness?