In reply to Graeme Alderson: Apologies for the quick hijack...
Yeah, had a google earlier.. read this on here but they don't give an original source..
http://www.xmarksthescot.com/forum/f260/ian-john-sean-68361/
"Found this on-line regarding the name John:
English form of Iohannes, the Latin form of the Greek name Ιωαννης (Ioannes), itself derived from the Hebrew name יוֹחָנָן (Yochanan) meaning "YAHWEH is gracious". This name owes its popularity to two New Testament characters, both highly revered saints. The first was John the Baptist, a Jewish ascetic who was considered the forerunner of Jesus Christ. The second was the apostle John, who was also traditionally regarded as the author of the fourth Gospel and Revelation.
Greek form of Yochanan (see JOHN).
VARIANTS: Ioannis, Yannis, Yiannis, Yanni, Yianni (Greek)
FEMININE FORMS: Ioanna (Greek), Ioanna (Biblical Greek)
OTHER LANGUAGES: Gjon (Albanian), Yahya (Arabic), Hovhannes (Armenian), Jon, Ion, Ganix (Basque), John (Biblical), Yehochanan, Yochanan (Biblical Hebrew), Iohannes (Biblical Latin), Yann (Breton), Ioan, Yoan, Yan, Ivan (Bulgarian), Joan (Catalan), Jowan (Cornish), Ghjuvan (Corsican), Ivan (Croatian), Johan, Jan, Ivan (Czech), Jens (Danish), Johannes, Johan, Jan (Dutch), John, Shawn, Shaun, Shane, Sean, Evan, Ian, Ivan, Shayne, Jon (English), Johano (Esperanto), Juhan, Johannes, Jaan (Estonian), Juhani, Juhana, Jouni, Joni, Johannes, Janne, Jani (Finnish), Yann, Jean (French), Xoán (Galician), Johannes, Johann, Johan, Jan (German), Keoni (Hawaiian), Yochanan (Hebrew), János (Hungarian), Jón, Jóhannes, Jóhann (Icelandic), Shane, Sean, Seán, Eoin (Irish), Giovanni (Italian), Johannes, Joannes (Late Roman), Jānis (Latvian), Sjeng, Sjang (Limburgish), Jonas (Lithuanian), Jovan, Ivan (Macedonian), Juan, Ean (Manx), Jan, Hann (Medieval English), Jehan (Medieval French), Jens (Norwegian), Janusz, Jan, Iwan (Polish), João (Portuguese), Ion, Ioan (Romanian), Ivan, Ioann (Russian), Jon, Johannes, Johan, Jan (Scandinavian), Ian, Iain, Eoin (Scottish), Jovan, Ivan (Serbian), Ján (Slovak), Žan, Janez, Jan, Ivan, Anže (Slovene), Xuan, Juan, Iván (Spanish), Jens (Swedish), Yahya (Turkish), Ivan (Ukrainian), Siôn, Iwan, Ioan, Ifan, Iefan, Evan, Ieuan (Welsh)"
So some clade (I put clave before.. no idea why)