I just found a pair of mimmoths in book 2, after Agatha and her fellow hostages/students on the flying castle sneak a look at the hive engine, and then go running so they aren't caught. One of the characters pretends to be a mimmoth exterminator, and sure enough, careful inspection of the page shows them hiding atop some sort of cabinet.

And, I will add, your CD arrived today alongside Mary's.

Might I enquire to ahsk the significance of "I promised Eli?"