Not yet, but I'm working on it!
A friend of mine had read 'War and Wine' about the German occupation of Northern France (from the Loire up) during WW2. One of the premises of the book was that before the occupiers arrived, a lot of the Chateaux and larger houses hid many of their valuables in cellars and then bricked them up, so that they were safe from 'appropriation'. Then of course, the houses would be occupied, the owners 'relocated' etc etc. And of course, over a 5 year period, people die, never come back or simply forget.
So now, the Brits buy up these houses, 60 years after the event and never question the layout of cellars, walls etc etc.
So, once I have worked out a suitable system for sending webcams into small holes.........
And then of course we almost all have wells over here. And where better to hide stuff quickly. But wells contain water and quite often stones etc fall and cover the bottom. So how do I search the bottom of a 5-10M deep well (with typically a 2M depth of water) for treasure? I did ask my sister if I could borrow her youngest boy, so I could dangle him upside down from the bucket holder and lower him down to look but she refused.
I can see that book taking up a fair bit of time