I skipped this one back in Chicago 2016 as I'm not a fan of Eva Green, and Tim Burton is too hit-and-miss for me to have any expectations. Well, now I wish I'd seen it on the big screen. Green is excellent here, suitably arch and headmistress-y. Doubtlessly this is some kind of riff on the Harry Potter universe, where Burton shows what can be done if you like it out in Army of Darkness and Corpse Bride territory.
The plot is not worth remarking on, and things go as you might expect. The time stuff didn't strike me as especially coherent or problematic; it allows Burton to escape to the great days when Britain was relevant and not so entirely self-absorbed (1943). Too much of the setup is told not shown, and for some reason Burton feels the need to ground this fantasy in reality with a somewhat tedious first 20-30 minutes of bored-in-Florida; somewhat like Peter Pan perhaps. His take on American parenting is brief, comedic and brutal. Asa Butterfield has the occasional stumble in the lead; conversely his romantic foil Ella Purnell is rock solid, as is Terrence Stamp in (straight) grandfather mode. We get some coming-of-age realisation. A highlight is the stop-motion battle scene at the house. I wonder what's in the books.