When using the online data users should be aware of the following.
In a small number of cases in the Castlegregory Roman Catholic marriage dataset the date of marriage is out by a century i.e. 1856 instead of 1956.
In that parish (and I think others) the address of the groom was not usually recorded up to the advent of Civil Registration in 1864. Only that of the bride was recorded before 1864. In the online version this information is incorrectly presented as the address of the groom.
Also, in Castlegregory, the name "William" in the original register has usually been transcribed as "Gerald". This applies to children grooms, fathers
The above should not take from the imnmense value of the online data.