We haven't been back for a while but I wondered if you ever checked out these and had any thoughts on their status?
http://www.themodernantiquarian.com/post/52387/poppy_stone.html
http://www.themodernantiquarian.com/site/8965/ty_newydd_stone_row.html
As regards the Poppy Stone - haven't had the pleasure as yet - Coflein cite it as a 'Standing Stone' of unknown period at Pen y Rhiw Iar (unless I'm looking at the wrong stone). Let's just say it looks the part and certainly would not be out of place. Do we need to excavate the footings of every hillside monolith to prove it isn't a scratching post? It certainly doesn't look 'natural', an erratic etc.
The stone row also looks the part... trouble is rows with (relatively) large stones are at a premium in Wales. However this does lie in the area between the Saith Maen and Rhos-y-Gelynnen, so there is at least some precedent.
Postie?