You might as well have given readers the rest of the fairy-tale. That the Destiny Stone was originally Jacob's pillow (Genesis 28) and was carried by Pharaoh's daughter Scota and her boyfriend, Gaythelius, to Ireland.
Only the completely cuckoo and the cunning place any credence on the Lia Fail hokum. That the Tories hope to gain some electoral advantage by returning it shows how daft and desperate they are.
Better by far to take the thing up in a helicopter and drop it into the deepest part of Loch Ness. With luck, it might brain the Monster and so kill two Scotch myths with one Stone.