I have decided to share my thoughts and theories with regard to the hunt. I am now 70 years old, have visited France once and will probably not be going again, so hell why not. Take my theories as they are or ignore them totally, it’s up to you. They are not in any order with regards to the clues, just as they come to mind.
I will start with the 4 centered spiral. Imagine an electricity pylon with 4 legs (centers), then imagine a square helter skelter. The diagonal struts when followed to the top form a square helix. These are everywhere in the Dabo area, which I believe is the location.
The Rock of Dabo has to be The Black Perched ship. The figure of Pope Leo IX perched on the chapel has a papal ferula in his left hand, probably depicting a key if you look carefully. The chapel could also contain the becalmed Nave, but I believe this also fits another clue.
I have more clues but cannot wok out how to insert images as it becomes too complicated to explain without them.
I will post more thoughts when I figure out how to do that.