I'm guessing Agnes Hatton is Eileen/Nellie's half sister
There's the mixed Hatton/Lynch collection of lodgers in 1891 - William Hatton (b Cornwall) and Susan Hatton (42 b Ireland) David Lynch b Winchester, Nellie Lynch b Portsmouth and Agnes Hatton b Northants
1871 - Winchester
James Lynch 20
Susan Lynch 22 - b Ireland
Catherine Lynch 1
David Lynch 4 Months b Winchester
David Lynch 13
RG10, 1211, 58, 28