William BOFFEY married Sarah ASTBURY in 1861. She looks to have died and been buried 24 Sep 1870 at Whitegate. So william in 1871 would have been a widower with 3 children. I think it is likely that his niece Mary came to help with the children and stayed on. It is forbidden for a man to marry his niece, so there was no marriage. Also, unlike the older children, I can find no baptism for Annie or Kate (illegitimate, father William, mother probably Mary), although their births appear to have been registered.