Thanks Fiona At night, the dark room is definitely a sleep cue, and she has a feed just before all of her sleeps so that's one too. Good point about the rolling, I hadn't even considered that.

We do have a sleeping bag with sleeves, and her little pyjama suits have parts we can put over her hands, but she can still get to her face so I have to wrap her with her hands down. I'm wondering if it'll get better when she grows out of the startle reflex? Maybe that's what's making her arms come up?