The use of the name Llanfihangel Rhydieithon appears to be unique to OpenStreetMap and not in current use anywhere that I can find except for a reference to it at GENUKI and even then there is no explanation for it. I suggest that the place name is restricted to Llanfihangel Rhydithon.

The location itself is rather loosely defined anyway but may be better placed where I've put it.