Perhaps this was covered in the previous thread, but did OP ever check the parish register's for his grandfather's baptism, and that of his grandfather's sibling?
Even though the civil registration did not name the father, parish registers often did.
What religious persuasion were they?
Hello,
My grandfather was Catholic and so were the couple he was living with when he married my grandmother. I'll see if I can find all local church records to where he was born to see if he is mentioned. If they are not online, I won't be able to do that.
As for his family being McCormick's, probably not as I have found no connection to McCormick's other than who he was living with and possibly where his name came from. My grandfather was living with a man named Daniel McCormick who was originally from Cluntagh towland, Crossgar, County Down. His father was John McCormick, so I am guessing at least maybe where his middle name Daniel came from if not his first name too? That doesn't mean I am related to McCormick's as I have found no evidence I am and no DNA matches to anyone related to these McCormick's.
I assumed if you read the original post link I posted to the original topic I made, that Daniel's wife, Annabella McKnight was related to Margaret since they both have the surname McKnight, but I couldn't find any record of Daniel and Annabella's marriage anywhere which might have listed her father's name.