Thanks, unless there's something wrong with her, I think she's definitely moulting. Apart from the dropping feathers, I saw some new feathers coming through all red which I gathered are these "blood feathers" I'd seen mentioned. She doesn't seem to like getting patted on her head as much when she's got a prickly head, I gather it's uncomfortable for her. Her beak is a safe patting zone at the moment. (I said in OP that it's the middle of summer, obviously it's not, it's towards the end).
I've never really noticed her moulting, although that's probably because she was in her outdoor house and she's been indoors with us.