I'm finding this book hilarious in that I'm pretty sure I've sussed Morton's tactics - an endless cycle of alluding to something happening, but not actually telling the reader what is happening.
It seems to be Morton's m.o.
For example, Percy intercepted a letter, tore it up and put the pieces in her trouser pocket. However she forgot about this, and when her sister comes across the pair of trousers (when doing laundry) she finds the torn letter.
We know this is an important letter, but we don't know what it says or why it is important. Morton withheld this information.
Now that the letter gets a second airing - even if torn and jumbled - we still don't get to know what the letter is about because Percy's sister is called away and does not have time to assemble the pieces of the letter...
Morton really does this all the time. It's meant to create suspense, but is ultimately utterly frustrating. I think Morton is setting herself up to fail here. There are so many loose ties that it will be night impossible to clear them up by the end of the book. Even if it is a gazillion pages long.
Also, I've come across another element that is basically the same (in principle) as in The Thirteenth Tale:
For although Percy had gone along with her twin's certainty that Juniper, if engaged, would have told them the news, in reality she had no such confidence. It was the sort of thing that people did tell one another, that was true enough, but Juniper wasn't like other people: she was beloved but she was also undeniably singular. And it wasn't only the lost time, the episodes: this was the little girl who'd comforted herself by rubbing objects on her naked eyeball - smooth stones, the end of Cook's rolling pin, Daddy's favourite fountain pen; who'd driven away countless nannies with her incurable obstinacy and refusal to abandon imaginary cohorts; who, on the rare occasions she was induced to wear shoes, insisted on wearing them wrong-footed.