The missing sister Mary!
Well after all this searching I thought OK no more surprises until now, looking at both census of 1901/11 I thought I had the whole family but not so.
Mary born 10 July 1891 married John Grant 1911,
I can only presume either the parents had little money or Fanny was finding it difficult to cope with 2 young babies so she was passed of to another member of the family. I have found one of Mary being a niece with the farren family but records of marriage, ages, don't add up nothing new there.