La Cerradura Doble - sliding key puzzle

#La Cerradura Doble

This is a remake of a puzzle I've seen online: http://smallpuzzlecollection.blogspot.de/2011/11/la-cerradura-doble.html. The original puzzle was limited series only and is long sold out, but I figured out from a photo how it went together and decided to remake it to have a try at solving it.

I have not invented the puzzle itself, however the printable 3d-CAD design (including all the engineering that went into making this printable from opaque plastic) has been made b