Are you looking specifically in Sligo for a reason as
in Ireland between the years 1846-1864 there are 1,523 Grady's listed, of which thee are 80 in 1858 in Sligo.
Griffith Valuation www.askaboutireland.ie
1901/1911 Census www.census.nationalarchives.ie
214 Grady's listed in 1901. 216 in 1911www.familysearch.org
will have civil births, marriages and deaths from 1864-1950www.groireland.ie
Civil Registration bmd copies of certificates.
Before 1864 all records were Parish records, most counties on line www.rootsireland.ie