I have gone over all of my answers and i think i have found a few things that most people would have missed,obviously i can’t go into too much detail until i have been over to try myself first but i am happy to update you as soon as i’ve been over.
I would like to collaborate with someone if they feel they are close too.
I feel i have an ‘X’ marks the spot.
Good luck with your solution! I have an idea of a place to dig too. I found this interesting about what to expect at the owl ‘burial’ site. It seems to be buried about 50cm from the surface. http://ilotresor.com/la-cache-de-la-chouette/