Maurice, The Catherine Moore in 1901 census, a visitor to N. Ireland was probably Catherine (Katy) Moore (nee Keays) half sister to William Henry (Willie)Moore. Willie's mother Margaret Watson married John (Jack) Keays 14. 08.1875
At first I thought it could have been Willie's wife Catherine ( also Katy) but she & Willie are on I.O.M. census 1901 living with her McAleavey parents and two small sons, Bernard & Robert. She had another son Albert in May 1901 and my mother Margaret was born 1904.
I would love to see copies of the letter & photos sent to your family by my grandfather, if possible.
Catherine Keays 1876-1965 married Ambrose Moore. Her son Alfred Douglas Moore wasn't born until 1902, so it was most likely that she was the young lady who came to visit her first cousin Catherine McKinn (Cowell). Marie Radcliffe email normar@manx.net