Thanks for the advice re: A2A.I have to admit, I've already looked at A2A and noticed the Humphrey BLACKMORE references; unfortunately, I don't think they refer to "my" Humphrey BLACKMORE, as they seem to be too far away from Churchstanton, but you can never be sure.
Since I last posted my plea for help, I think I may have sussed out who Humphrey BLACKMORE's parents were. It's slightly confusing (isn't it always?!):
"My" Humphrey BLACKMORE would seem to be the son of ANOTHER Humfry BLACKMOORE (notice slightly different spelling, from Parish Records!).This first Humfry BLACKMOORE appears to have been born circa 1635, probably Churchstanton.He married a lady called Mary (surname unknown/date unknown) and they had the following children:Thomas (1663); Sarah (1665); Nicholas (1667); Shadrack (1670); William (1672); and Mary (1676).I had already calculated that the later Humphrey BLACKMORE was probably born around 1660.This would fit in quite well; it's quite normal for the first-born son to be named after his father.
After that it gets REALLY confusing, but I won't destroy your peace of mind!