There is one marriage record on www.rootsireland.ie/ of Owen McAndrew to a Bridget but her surname is Kelly; neither bride or groom's parents' names are on the record however:
Date of Marriage:05-Nov-1854
Parish / District:LACKEN
No luck with Owen's birth / baptism 1832 + - 5 years in any county
There are 102 records for Bridget Flanagan birth 1835 + - 5 years including 4 from Mayo; however, that would make her only 5 years old when John Walsh died in 1840. Should it be 1815 or 1825?
I couldn't find a John Walsh - Bridget Flanagan marriage until 1878 in Offaly