1891 census
3 Station Rd North, Bexhill
James AVENDER 36 Gen Labourer, Sussex Hellingley
Ellen 27 Lincolnshire
Ruth 6 Lincolnshire
1881 census
66 Commercial Rd, Grantham
Henry COOK 44 Lab in Brewery, Ropsley
Rebecca 40 Marston
George 14 Errand boy, Spitalgate
Betsy 12 Spitalgate
William Henry 4 Spitalgate
Ellen AVENDER (sis in law,mar) 17 Soldiers Wife, Marston
Marriages Mar 1881
AVENDER James Eames, Hartley Wintney 2c 237 - this district is in Hampshire
to
PERRY Elen Hartley W. 2c 237
or
PERRY Mary Ellinor Hartley W. 2c 237
I believe Henry COOK (with whom Ellen was staying in 1881) was married to Rebecca FLOWERS, so I'm struggling to find a connection at present.
EDIT: Ive now found a Mary Ellen FLOWERS bap at Marston 24 Jan 1864, dau of Eliza ... Eliza appears to be a sister of Rebecca, so "sister in law" apparently means "niece".