Dear Philip
Very good to hear from you. I did know of your existence from May Skuce's daughter, who visited us in the 1970s. My father last visited Derrynafulla in the 1930s!
Our mutual great-grandfather George Nolan Cooper was the son of a Head Constable in the Royal Irish Constabulary. He and his brothers all followed suit by joining the RIC. George was posted to Cork, where he met Margaret Emma Smith. They were married at Christ Church (Holy Trinity Parish), South Main Street, Cork. He was then posted to Glengarriff, where he served from 1892 until his death in 1919.
Margaret Emma Cooper nee Smith already had a connection with Kilmacomogue Parish, her mother being a Vickery from Whiddy Island. Her father came from the Isle of Man, joined the army and served in the Crimean War, Indian Mutiny and Cape Colony before being posted to Bantry, where he met and married Kate Vickery. He was promoted to the rank of Sergeant on the day before his marriage in 1867 and moved to Cork after leaving the army.
The Cooper family can be seen in the 1911 census,
http://www.census.nationalarchives.ie/pages/1911/Cork/Kilcaskan/Cappyanghna/376340/ , but Margaret Emma died in childbirth the following month. As you will know, May Cooper, the eldest daughter, married Dick Skuce from Derrynafulla in 1916 and went to Canada. William Valentine Cooper, the eldest son, joined the Irish Guards and was killed at Passchendaele. I've obtained photocopies of his service records from the Irish Guards. With the exception of your grandmother, the family dispersed to the north of Ireland, England or further afield.
I've added some details at ancestry.co.uk if you have access to that site.
Kind regards
Michael (Cooper)