I am fairly certain the above information is correct, but is the any more information out there ??
I have found one lead which looks hopeful, which popped up after a bit of googling. I found reference to an archive of material in the "relating to the extended Ternan family and their friends, [c1800-1974], including; manuscript material received by Katherine Longley from Helen Florence Wickham as joint executrix and legatee of the personal property of Gladys Eleanor Wharton Reece (daughter of Mr and Mrs George Wharton Robinson)" These include material relating to Helen Wickham's career as an artist and miniature paintings by her of the extended Ternan family. Another reference to the same archive refers to Helen Florence Wickham as the foster daughter of the actress Ellen Ternan.
Miniature paintings by her included in the archive are portraits of Mrs F.E.Trollope, Sir John Martin Harvey as Sydney Carton in 'The Only Way' and Rosalind Wickham. Other references to Helen include Thirty letters to Helen Wickham regarding the exhibition and sale of her pottery figurines. Including correspondence with the British Institute of Industrial Art, The Royal Society of Miniature Painters, Sculptors and Gravers, the British Empire Exhibition, H.C.Dickins, the Fine Art Society, Ernest Brown and Phillips.
Internet references includes;