[davemac]

Originally Posted by MargaretR

More likely to have originated from -

kopje - definition of kopje by the Free Online Dictionary, Thesaurus and Encyclopedia.
kopje koppie
noun (S. African) hill, down (archaic), fell, mount, height, mound, prominence, elevation, eminence, hilltop, tor, knoll, hillock, brae (Scot.) the rocky kopjes, small hills rising like islands

Not convinced, but will keep an open mind.