One of my great-grandfathers was born in Daingean, so I have all of the pages from the parish register downloaded already, and I took a look to see whether I could find your Flanagan-Connor marriage a bit earlier, in 1843, because I was curious as to whether there was a connection to my family (I have distant Connor and Flanagan relatives, but the names are very common in the area). In doing so I found something odd. I continued into 1844 without realizing it at first, and on February 15th there is a strange entry, in a large space in between two other marriages about one-third of the way down the page. For the other two marriages, the full info is given (and in one the bride was a Margaret Flanagan, interestingly), but in the middle of that large space it just says "Flanagan to Connor", with no other associated names, and to the left of that is a big circle with three X's or crosses in it. Perhaps the priest realized that he had forgotten to note down all the info and marked it so that he could go back and fill it all in, but if so he apparently never did that (perhaps he had confused it wth the Margaret Flanagan marriage). There's no guarantee that that was your Flanagan-Connor marriage, but it's quite a coincidence. In case you want to check it out yourself, the page is image 211 in the Daingean/Philipstown marriage register covering 1820-1855, and I'll try uploading the image here when I complete this response.
Just FYI, Philipstown was founded in the 1500's as part of the "Marian Settlement", when Queen Mary I ("Bloody Mary") tried settling "loyal" Englishmen in what is now Offaly, which had been newly created by her as King's County, and Philipstown was named for Mary's husband, Philip II of Spain. When the Irish Free State was created in 1922, Philipstown was renamed Daingean, and the county was renamed Offaly. The full Irish form of the name Daingean is An Daingean, meaning 'the fort', and it is also referred to as Daingean Ua bhFáilghe (Daingean Offaly), because there are other places in Ireland named Daingean. The Catholic parish is still called Philipstown, since the Catholc parishes were largely set up back in the early 1800's, and do not always correspond in name or in their boundaries to the old civil parishes (the Catholic parish contains several of the old civil parishes, or parts of them).