I came across this message rather by accident, but may possibly be able to help. There is an Arthur Stert in my family tree born 28th Feb 1864 in Great Malvern (also I think in Worcs England - may be the nearest large town to Upton). He married a Mabel Austrian (or possibly just someone called Mabel who was from Austria) and had children Arthur and Dorothy - it just says 'issue in USA' for these two.
My great grandfather is his younger brother Lionel Stert (b 25th Feb 1865) who married Marion Patricia Molesworth. He lived in Denver for a while (as my grandmother was born there) but then returned to England.
If you think this is a match let me know, as I have quitea lot of information on the Stert family which was compiled by my great aunt.