I’m not surprised by the Saxon error. The Welsh name, “Cerrig Tan” is also wrong.
Fire is “tân”. I know it looks similar, but it’s a different word with a different meaning altogether and makes no sense without the circumflex above the a.
Also, in the interest of clarity and correctness, “cerrig” is the plural form of “carreg”, so “Cerrig Tân” literally means “fire stones”.
As for “y Berwyn”, well that’s not even close. Considering the site itself, I don’t understand how anything to do with mountains has got to the shortlist. Suggested by many in faraway English cities, perhaps …”Wales = mountains”? But why approved by the panel of locals?