Hi Lynne,
Lots of people on RootsChat are willing to help and some might have the resources if they are given the information, even though they may not be related.
I'm not sure if I have got this right, but if Doris is the sister of Fanny what is Fanny's DoB ?
Jane Armstrong nee Partridge would have been 43 in 1904, if she is the mother then she would be towards the back end of her child bearing years ? How much younger does the Doris in the photo look ?
Dave