His Wikipedia entry is here. Art Renewal Center's take on his is here. Clearly, Spencer-Stanhope knew and was influenced by Pre-Raphaelites and their Victorian successors, particularly his friend Edward Burne-Jones. And the renewed interest in that aspect of art history has led to rising prices for his works.
Below are images of some of his paintings in chronological order by year.
Although all the details differ, this reminds me of "Mariana," a 1850-51 painting by John Everett Millais.
Any allegorical or symbolic meaning in this painting was more clear to viewers in 1860 than it is to me in 2017.
A Shakespearean subject.
Lacking a 19th century elite British education, the reference of this painting also escapes poor me. However the Tate offers this discussion regarding it.
The title is a line from the poem 'The Earthly Paradise' by William Morris.
Very Burne-Jones- like. Spencer-Stanhope painted several close variations on this, but titles differed.
Note the similar stylized appearance of the males in this image and the one immediately above.