Hi Jane, a shot in the dark, but I thought I was aiming rather well.
Henry Becher married (presumably in the East Indies) and had two perhaps three children born there between 1800-1815--Margaret Pereira Becher, Henrietta Becher and Henry Becher. Henrietta grew up in Southwell so presumably they moved back when she was young. Her children were said to be "dark" like her so presumably she got her colouring from her mother. Since Henry didn't married again until the 1820s I assumed his wife must have died at Southwell in the interval.
Thanks, Laverdiere