Falcon and fetterlock

This symbol - a Yorkist badge from the Wars of the Roses - appears all over Oxburgh Hall. I didn't know what a fetterlock was but learned yesterday that it is a D shaped metal device designed to lock around a horse's fetlock to which a rope could be attached to tether it. In most of the examples of this symbol - carved into wooden panelling, stone walls, embroidered on chair backs etc - the fetterlock is closed. (See extra for a rather poor picture taken with my phone of the very top of the panelling in a poorly lit high-ceilinged room.) However, in the dining room there is a tiled fireplace surround where the fetterlock is depicted as open.The family has always been staunchly Catholic and after the reformation it was illegal to practice Catholicism until 1791. The illustration of the open fetterlock on this tile  was a coded declaration of the defiance of the family against the persecution - a symbol  of freedom, not restraint.
I don't usually use my phone for pics - but although I had my camera in my pocket, the spare battery was in the camera bag in the car!