Searching for family of British world war pilot

I am researching the family background of Edward ‘Mick’ Mannock, the greatest British air ace of World War 1.

His parents, Edward, a soldier, married his mother, Julia, from Ballincollig in the local church of St Mary and St John in February, 1883.

A younger sister of his, Helena, married Jim McIntosh in Belfast in 1917. I understand her descendants live in the Cork area.