Thank you all, for your help. I'd be really grateful for your opinions, as you obviously have much more experience of dating photos than I have.
It's actually opened up more possibilities. I thought I knew who the lady probably was - my grandmother's paternal grandmother, Jane Tindall, who lived in Scarborough. However, the mention of Falsgrave reminded me that was where her maternal grandmother, Ellen Maltby, came from. Although Ellen later moved to Hull, there were obviously still connections with that area.
So, I'd be really grateful to learn how old you think the lady in the picture is. Ellen was born 1839 and Jane was born 1817, so if I take sutton Rog's dating of late 1880s, then the age of the lady could be the decider.
And now we can see her clothes more clearly (thanks everyone for that), do you think she is in mourning? That would be another clue.
Thanks again everyone. I'm very grateful for all this help.
Lesley