Sidney as a female name

I've just been reading "A suitable vengeance" by Elizabeth George, and have found it rather disconcerting to read about a female character with the name "Sidney".
I've never encountered a female Sidney in real life, and the image that comes to mind is my wife's uncle Sid, who was a rather boring old geezer with grey hair. Calling an (apparently) glamorous female character "Sidney" is a bit like calling one "Alfred" or "Stanley" or some other popular Victorian/Edwardian male name.
I've read a number of other books by Elizabeth George she writes wodunits, featuring Scotland Yard detectives Thomas Lynley and Barbara Havers, and their friends and colleagues. Among these are Simon St James, who is both a friend of Lynley and a specialist in forensic medicine. The Sidney is Simon St James's sister, but doesn't appeaer to feature in most of the novels, which is why I've only encountered her now.
My question is, has Sidney become a common female name in Britain? And if so, when did it become popular? Has anyone else encountered female Sidneys, in literature or real life? Am I the only one who finds this strange as a female name?
To genealogists out there - has anyone found a female Sidney on a census? If anyone has the 1881 census discs, is it possible to search for the number of Sidneys, and see how many are male or female?

Steve Hayes
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Web: http://www.geocities.com/hayesstw/stevesig.htm http://www.geocities.com/Athens/7734/books.htm