Hi mmkiwi,
Pauline has been on Rootschat since mid 2015. If she is still around or has the same email address she should reply to your query.
A Tree has Louisa Parents as Francis FINNIS and Mary Ann BELVILLE 1798
There is a Birth Reg for a Louisa Frances FINNIS 1838 Worthing on FreeBMD.
They have no date for the Marriage of Francis/Mary Ann or Census details.
What I have found is;
1841 Census
Broadwater, Sussex
HO107/1095/2/Broadwater
John SMITH, 35, Shoemaker
Mary FINIS, 35
Richard Finis,12
Jane Finis, 10
Sarah Finis, 8
James Finis, 5
LOUISA Finis, 3*****
William Finis, 1
John Smith and Mary Finnis are NOT born in County.
Francis FINNIS Married Mary Ann BELVILLE, 13 Feb 1821, St Mary, Broadwater, Sussex
Witnesses John Belville and Sarah May
John BELVILLE Married Sarah MAY, 17 Feb 1823 same hurch
FRANCIS and MARY Finnis were Witnesses
A John FINNIS Married Rebecca BELVILLE 16 Nov 1832 same Church
BAPTISMS;
Broadwater, Sussex
FRANCES, 10 November 1822
FRANCIS, 4 July 1824
MARY ANN, 16 April 1826
RICHARD, 20 January 1828
ELLEN, 17 November 1829
SARAH, 31 July 1831
CATHERINE, 8 May 1833
Parents FRANCIS and MARY Finnis
(Familysearch.Org)
BURIAL;
FRANCIS Finnis 21 July 1833, Broadwater, Sussex
Age 35, Birth c 1798
(F/S.Org)
So looks to me that Francis died soon after Catherine was born and the later Children are illegitimate.