Hi Justin
I think we've clarified this some years ago, but I just came across your posts re my grandparents: John and Annie Jones. And they are of course Ceridwen's and my father John's parents.
Great research by you and others. My father was John Emrys ( first names) Jones. Emrys came from his uncle I'm pretty sure - one of John senior's brothers. As you say, my father added Emrys to Jones and made that the surname sometime after my birth in 1942.
Annie was also a Jones. And from Morfa Buchan. She and John snr. married in Wandsworth. They moved to Pentre in the Rhondda valley of South Wales in the late 1930s I think. Annie, according to Ceridwen, claimed descent from a Baron Owen. I've not traced this. All best. Michael