I have been looking at the 1881 census for England, but think that you family may have been born after that. I wonder if the following could be in anyway connected to your Ralph (although he would be a lot earlier), with the naming pattern:-
Ralph COXON baptised July 29th.1759 at South Shields. Parents: James & Mary.
Most of the Ralph COXONs I found in County Durham came from around the Chester-le-Street area. I found a later AVES marriage in Durham, wondering if Isabella was connected to that family:- Arthur AVES (22 years old) married Mary BELL (19 years old) at Durham St.Margaret on May 13th.1899.