Maybe because the Great Orme is Craig y Gogarth in Welsh?
Now there's something I didn't know, cheers.
Am at home now and have an old map of North Wales (Bartholomew's Revised "Half Inch" Contured Map, No 27 Price 7/6 Net) and it is indeed marked as Gogarth on there. The Gogarth on Angelsey is marked named Gigorth Bay.