Hi Gavin,
I have no doubt my Grandfather and yours knew each other, they both lived in the same tenement, most probably drank in tbe same pubs, Bridgeton had a large first and second generation Irish community hense the Norman Conks, the largest Protestant gang in that area was the Billy boys which still exists to this day but under a different name (Bridgeton Derry), my grandfather was Catholic but i'm sure there was some as you say "iinter mingling" back then.
Regards, John,
Have a happy and safe Christmas.