My paternal grandmother, who was born in Surrey but lived much of her life in Hawaii, liked to be called "TuTu" (Hawaiian for grandmother), but said anything was OK except "Granny." When I was 12, I started calling her "Granny," and she retalliated by calling me "Johnnie -- well, he is John E., you know." This good-natured "feud" lasted until she died several years ago, at 92. When I needed a forum handle, this seemed like a nice memorial.
The Eldon surname apparently goes back to clan MacIntosh, as a variant of "Elder." By tradition, the firstborn males have been named John and Charles in an alternating generational pattern.