"All we have."
Now that Bowe, Bowes and Crowley have all tested 67 markers, it's clear that Crowley does relate to this Bowe and Bowes. Looking at the genetic distances between these three, since the time that surnames came into use (about 900 A.D. in Ireland, and 1167 A.D. in England), it's likely that Crowley's line had once been Bowe/s and along the way became Crowley. This is also suggested by the fact that, so far, while this Crowley matches Bowe/s, he does not match any of the over 70 other Crowleys in the Crowley Clan study at FTDNA. This indicates some sort of "non-paternity" event, such as an orphan taken in by another family (this was not uncommon when parents more often died young), an affair, or some other situation.