It might help to see a larger version of the picture. I think the item in her hands, and the photo album are clues, as photographers often used props to tell more of the story. I would say the woman was older than 40 (more 60-70 yrs, so if photographed C1890 then born C 1820-30). I'm not very familiar with fashions, but I have done a small amount of study on fashions and photographs in the past, and ladies (widows) of this time period wore a lace cap as a sign of mourning. Check this notation copy/pasted from the link which follows. You will need to look at the 1890's fashion, and scroll along a bit.
Portrait of Lady Duckworth, F. Hollyer
Portrait of Lady Duckworth
Frederick Hollyer (1837-1933)
About 1890
England
Platinum print
Museum no. 7835-1938
This portrait of Lady Duckworth shows her in Victorian mourning dress. A widow was expected to conform to strict rules governing her clothes for at least two years after the death of her husband, which included the wearing of a widow's lace cap and a black cape as seen here. A younger woman might discard her mourning garb after two years, but elderly widows generally wore it for much longer, if not the rest of their lives.
http://www.vam.ac.uk/content/articles/h/history-of-fashion-1840-1900/
Thomas John Kerslake (wife Bessie E) was born in Devon, Exeter. He is age 26 and a Photographic Artist at 62 Regent Street in WSM in 1891. He was a photographer for at least 20 more years in WSM at a different address.
Given the woman's dress, and the location of the name of the photographer on the picture it seems the woman was photographed very late 1880's or very early 1890's (as someone may already have said.)
In case you ahven't seen it, this is a link to a quick-look of fashion dates - general ideas, of course, given that not everyone was up to the minute in fashion.
http://www.rogerco.pwp.blueyonder.co.uk/time/time.htm
Good luck finding the identity of your lady.
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