Thank you for your research regarding the origin of "Upsher, et. al.". I looked into place names as well. "Upshire" as you note was a hamlet in Waltham Parish, Essex County. I also found an "Upsher Green" in Suffolk. Because Upsher Dolbee (Messick) was the illegitimate son of Constance Dolby (Messick), we do not know the birth father's name.
I assume that given names which designated locations were assigned to individuals whose surnames came from other sources (occupations, physical characteristics, etc.) in order to provide specificity.