My name is Harry Royle and I travelled from England to Cordoba, Argentina with my father (John Royle) and two sisters in late 1952, arriving in January 1953. My father took over an apartment in Cordoba and in one of the flats below lived Isabel Bottex Harrison with her young daughter Maria Cristina Bottex, then around 5 (I was just 7). Isabel had two older daughters called Virginia and Maria Amelia, aged in their early teens, I guess.
When Dad and I returned with my two sisters to Britain in December of 1954, Isabel and Cristina also returned on the same boat. Returning to Cordoba with my father the following year (March or April 1955 - my two sisters stayed behind in the UK) I discovered that Dad, Isabel, Cristina and I were to live together as a family. Until that point in time I had not been aware of a romance between the two adults.
If this is indeed the relative you are seeking (I remember on arrival in the UK in early 1955 Isabel and Cristina went to visit Cristina's "Uncle Corky" Harrison in either Newcastle or County Durham) then I can provide more details if you drop me an e-mail.
My father and Isabel split up in 1963, and I have had no contact with either Isabel or Cristina since. I'd be equally interested to hear any news of them which you may possess.
With best wishes