hey first post on here, but after spending a few days reading up, finally got the courage to join (and found something else to distract me from my degree! lol)
I printed out and took the photo to my geography lecturers and they said that the stone looks like sandstone and it looks like somewhere like Peak District area (New Mills is a possible), Cornwall or South Wales! As to what it is... no idea! it looks quite well constructed though - the planes in the wall are quite straight and even (unlike drywall), but the moss at the bottom of the wall does look like it's somewhere with water or north facing wall (photo taken looking south).
Just hoping for a clue... have had to get some wrist supports for my laptop as I'm spending so much time at it, looking for pictures!! lol