Since the father for this Rebecca baptized in Tullamore is John and not Daniel, then either this is a different Rebecca Bagnall to the one on your family, or there's a mistake on the marriage record.
The index on RootsIreland is showing two matches in parish records for the marriage you mentioned, both in 1872. For some reason there's two Tullamore CofI parish listed in the drop-down - possibly a duplicate.
I cant seem to locate any details using the free index on father's names.
The only record I can see for a George Bagnall with father either Daniel or John on RootsIreland is too recent - birth 1872 in Mayo with father John.
Shane