"Many modern Welsh parents have chosen place names as given names for their children, and some may be giving the name Alun through confusion with the river name, not realising that Alun is a well-established Welsh form of Alan."
Sorry Merriment, but you are not making any sense. You admit it is an old Brythoneg name, but then you say us modern Cymry are confused; well after speaking to you I sure am!!!
I have called my son Alun would you like to tell me why? But before you do, I'd just like to tell you, my father was called Alun, as was his grandfather, his grandfathers grandfather etc. Bit of a family tradition. (I am under no confusion about the name.)
Would you like to tell me that my surname isn't Cymraeg/Brythoneg either?