I have a note in my database that firstname.lastname@example.org posted the following dates for Marya:
born 11 June 1787, died 24 September 1844 in Farnum, Sheffield.
I've no idea what this person's sources were -- perhaps he or she got the information from you!Might be worth a contact...
At any rate, I don't have any other records listing Marya Flandrow.However, virtually all the American Flandrows I've come across from that period (whose birthplaces were listed) came from Westchester County, New York, and more specifically from New Rochelle.
Jacques Flandreau, the earliest Flandreau immigrant currently known, was an early settler of New Rochelle in the late seventeenth century.