I'm not too sure as to when Oliver became Olly for me. Somewhere in my single digit years the transformation was instigated by my schoolmates. My mother and my Two girls call me Oliver, as does my sister and her kids. My wife calls me OLIVER on certain higher frequency occassions. My preferred spelling is Olly, but I am also Oli, Ollie, Oly, Olay, Ole, anymore out there?