Do you know if Catherine raised son William?
Seeing your other post mentions a Dixon marriage that must have been important to him, there is this possibility:
Catherine Armstrong , father William Armstrong, married William Ridley Dixon, in Cumberland, 1868.
https://www.familysearch.org/ark:/61903/1:1:NXVT-ZV9In 1881, Newcastle-Upon-Tyne, there is a Catherine Dixon, father William Armstrong, marrying George Andres Watson. He is listed as age 33, and she at 30. In 1911, this couple has a boarder, John Armstrong, which might be her brother.
The occupation for George A Watson is a crane operator in a factory.... maybe they made masts there, which would fit your other post?
I haven't put much time into digging into these people; just noting that they are a possibility.
Edit: The William Armstrong in Cumberland, which I think is the father here, has a daughter, Catherine Dixon, living with him in 1871. No sign of son William though. (I think Ann is his second wife, too)