Hi Gladys,
Glad to hear from you.  I also 'think' that he may have returned to England at some point prior to the 1891 census.  Do you know of any way to check that?  I have also seen an Edward Potts as a laborer in Philadelphia in 1890, but by himself.  My Great grandmother shows up in the 1900 USA census with 2 of the children (my grandfather Robert and his sister Phoebe, both born in Easington), but no evidence of Edward.