Does Father Brown have a first name?

People debate about this one. Chesterton referred to him once as Father J. Brown, and a "narrator" once referred to him as "Paul", but on the whole, I wonder if Chesterton didn't intend for Father Brown to actually have a first name. The stories are set in the period between 1910-1936 (Chesterton died that year) and the later television series, based on those stories, is set in the 1950s). In both those time periods, Catholics or other people would never DREAM of addressing a priest by his first name. They were addressed as "Father" by everyone, even non-Catholics, and, when referring to them indirectly, as "Father (surname)". With Holy Orders etc, I seem to remember that Priests, Nuns, Christian Brothers and so on back then were supposed to give up all ties to their previous lives, including their baptismal first names. Sometimes their birth families never saw them again. They adopt another first name more related to some historically holy person or saint in the church. Two of my brothers, for example, both adopted other names on entering the church. So if Father Brown was referred to - once - as Paul, that may have been his chosen church name as in the apostle Paul.

http://chesterteens.blogspot.com.au/2008/06/father-browns-first-name.html
https://en.wikipedia.org/wiki/Father_Brown

Chesterton based Father Brown on the priest instrumental in his conversion who's first name was John.
But the only time I heard a priest addressed by his first name was when he was talking to another priest.
Not all priests change their names, the parish priests that I knew used the full name they were baptized,
The religious communities (Franciscan, Dominican and Benedictine)t
would change their name entirely; the sisters and the brothers who served in the parish.
If they were missionaries or contemplative(living in monasteries) they might never see their families again. But our parish
priests would take trips to Ireland at least once a year to visit their families.
https://www.goodreads.com/series/55609-father-brown