I'd not heard about Four Children and It either! (To say nothing of the Lamb.) Jacqueline Wilson is huge in the UK, but I remember hearing that she'd never broken the US market, so am unsure whether you'll know her. She specializes in first-person books, narrated by children in difficult circumstances (divorcing parents, in care, bipolar mother, etc.), and she does them very well. A few of her books have a fantasy dimension, but that's not what she's known for. I'm intrigued, but fearful.

I particularly wonder whether she'll keep it in Nesbit's third person, as I've not read a book by Wilson that wasn't first-person, and I've read quite a few. I'd have thought The Treasure Seekers would be much further up her street.