Hi Graham
An excellent starting point for surname research is the Irish Ancestors website at
https://www.johngrenham.com/surnames as John's ‘Surname search’ option enables you to examine the location, frequency and history of Irish surnames.
A search with surname Gready reveals the following number of households of the name in mid-19th century Ireland:
Clare 2; Cork 2; Galway 2; Kerry 1; Kildare 1; Mayo 9; Offaly 2; Sligo 1; Tipperary 3 and Waterford 1