This may be the marriage of Francis HANLON in 1888:

Name: Francis Hanlon
Date of Registration: Jul-Aug-Sep 1888
Registration district: Dublin North
Volume: 2
Page: 457
FHL Film Number: 101255

There is also a Maria Gavin on the same page, so a possible match.

There is a Francis & Mary HANLON on both the 1901 & 1911 censuses, although not sure if it's the same family on both as info differs regarding place of birth of parents, and number/names/children born.

Good luck!

Colette