I have been using Siouxzie, since I was about 11 (1973). Definitely before I'd heard of Siouzxie Sue and the Banshees, I think she copied it from me. It was more to do with my love of old black and white westerns on the telly of an afternoon and my sympathies lying with the native americans, I was a strange 11 year old. I used to make the S be a snake with a long forked tongue. But I too sign with my actual name Suzanne, as it seems more grown up, not that I am or anything.