I'm mopping up some outstanding bits of digging... hence the odd series of posts at the moment. (Hate to see this research going to waste and, you never know, a long lost relative may step forward with a ton of information to share).
Soooo.... Mrs B. Eaton-Back wrote a series of crime novels under the pen-name Derek Vane. I've never read any of them so I've no idea of their quality, but she appeared regularly in print between 1893 and 1934 and is likely to have been writing for the romance papers of the day (I base this on the fact that one of her novels was published by D. C. Thomson in their 'Red Letter' series, Red Letter being one of their weekly romance titles).
The only known fact about Mrs B. Eaton-Back was that she died in 1939. The latter was easy to check and proved to be true: Blanche C. E. Back died aged 83, her death registered at Hove, Sussex, in 4Q 1939. From her age it seems likely she was born in 1855/56, the latter the more likely.
So the first stumbling block was that of the four women born Blanche C. in that period, two could be relatively quickly dismissed as they married people with different surnames and two others seemed not to have married at all.
However, I did find one possible suspect: Blanche Caroline Duncan, whose birth was registered in Croydon in 1Q 1857. Legally births have to be registered within six weeks, so the January to March (1Q) records could include births as early as November 1856, which puts her in the frame. Christening records show that she was Christened at St. James, Croydon, on 27 March 1857.
The reason I suspected her was a search of the 1901 census where I found a Blanche C. Back listed as living at 2 Newburgh Road, Acton. The head of the household was one Ann W. Duncan, the widowed mother of the also widowed Blanche C. Back. Ann was born in Dagenham, Essex and can be tracked back to the 1871 census when the family were living in Lime Grove Park, Putney. At the time she was still married to John Duncan, a merchant (principally in sugar), and their eight children: Mary, Marianne L., Alfred Edward, Blanche Caroline, Ernest Arthur, Alice Emily, Louis Henry, Charles Percy. They had married in Romford in 1846, she being the former Ann Warren Boulton.
John (noted as living on income from land and bonds) and Ann had moved to Leonora Lodge in Finchley by the time of the 1881 census. John died before the 1891 census.
Blanch (minus the 'e') Duncan appears in the 1881 census a visitor at the house (in Hornsey, Middlesex) of Mary Beatrice Linster Simpson (a widowed Scotswoman). Interesting to note that Mary Simpson's children included two—Frank and Arnold—who both worked as clerks at a publishing firm (unknown which). It seems more likely that Blanche was visiting their elder sister, Juanita Isabel Simson, who owed her exotic name to her birth in Conception, Chile, and was around the same age as Blanche.
It seems that Blanche was married and subsequently widowed between 1881 and 1891. It has proved impossible to find a record of her marriage relating to Eaton-Back or just Back; however she is to be found, widowed, in the 1891 census as a visitor to Eaton Lodge in Putney, the home of John Pepper (a retired chemist) and his wife Mary Ann.
One of her novels, Lady Varley, was made into a silent film in America in 1923 under the title Modern Marriage, scripted by Dorothy Farnum, directed by Lawrence C. Windom and starring the popular leading man Francis X. Bushman, nicknamed 'King of the Movies'.
Blanche Eaton Back was living at 46 Gwydyr Mansions, Hove, when she died on 15 November 1939.
Novels as Derek Vane
The Sin and the Woman. London & Sydney, Remington & Co., 1893.
Estranged; or, Love Unquenchable. London, Aldine Publishing Co. (Masterpieces of Modern Fiction 11), 1894.
The Spell of Delilah. London, Aldine Publishing Co. (Masterpieces of Modern Fiction 21), 1895.
Verner Galbraith's Wife. London, Aldine Publishing Co. (Masterpieces of Modern Fiction), 1895?
The Three Daughters of Night. London, Hutchinson & Co., 1897.
The Mystery of the Moat House. London, (Cosmopolitan Series), 1901.
The Secret Door. London, Everett & Co., 1907.
The Paradise of Fools. London, Everett & Co., 1913.
The Soul of a Man. London, Holden & Hardingham, 1913.
Lady Varley. London, Stanley Paul & Co., 1914.
-?-The Ferrybridge Mystery. New York, Moffat, Yard & Co., 1920. [UK title?]
The Scar. London, Geoffrey Bles, 1924; New York, Edward J. Clode, 1925.
The Trump Card. London, Hurst & Blackett, 1925.
The Sign of the Snake. London, Hurst & Blackett, 1927; Philadelphia, Macrae-Smith Co., 1928.
Intrigue and Matrimony. London, Hurst & Blackett, 1928.
What Fools Women Are!. London, E. Nash & Grayson, 1928.
The Unguarded Hour. London, D. C. Thomson & Co. (Red Letter Novels 230), 1929.
The White Panthers. London, E. Nash & Grayson, 1930; New York, Macmillan, 1930.
£500 Reward. London, Eldon Press, 1933.
Who Goes There?. London, Eldon Press, 1933.
Dancer's End. London, Eldon Press, 1934.