den sure kalkun: I've heard from a reliable source that the cache has been muggled again. Since I don't have a container that will fit, and it will be a lot of work to change the puzzle to fit a new place, and because the place is obviously not safe from muggles, I will archive this with immediate effect. Sorry if anybody was working on it; I'm happy to confirm the solution / help with the puzzle if anybody still wants to solve it despite there being no cache reward. Just send me an email.
I will not place a new cache in this location.