I have reservations about The Children's Book too. I think there's something a little dodgy about rewriting an historical epoch with fictional characters standing in for real people. Byatt does the same thing in Possession- where she posits a love affair between two Victorian poets- one of whom is essentially Robert Browning and the other Emily Dickinson. She writes poems for her pseudo-Browning and her pseudo-Dickinson and they're pretty terrible.

I don't hate Byatt by the way; I think her short stories are wonderful.

I've no idea about the miniature cities. It would be wonderful if they still existed- but I have my doubts. Have you read The Magic City- in which a miniature city comes to life?