I saw this throw demonstrated earlier today in a children's judo class. The tori starts in a headlock (or perhaps puts their own head into one), pushes their inside arm through to grab at the back of the uke, and then steps through to catch their ankle. As the uke goes over backwards, the tori does a breakfall over the top of the uke (or to the side of their head if they're trying to be gentle).

The teacher didn't know the name of this throw, and said that it wasn't in the Kodokan set. He was unsure if there is a formal name for it.

Does this have a name? Most of the headlock throws I've found on Youtube look very different and have the person performing the headlock completing the throw. It seems like it should be sutemi waza, but the lists of sutemi I can find don't have anything that sounds/looks like it.