From the IGI

Ann is likely to be either:

BANKS, Ann d/o Wm BANKS & Alice (more likely Elizbth) COWEN chr 19 Jun 1791 Douglas, St Mathews, IOM

or

BANKS, Ann d/o Mathias BANKS & Ann CASEMENT chr 30 may 1792 Douglas, St Mathews, IOM

I think the latter, as there is an earlier marriage of an Ann BANKS to a Godfrey TATE in 1812.

Other Children of Mathias & Ann are:

BANKS, Ellinor chr 19 Nov 1794
BANKS, Ewan chr 27 Jun 1804
BANKS, Cath chr 02 Jun 1799
BANKS, Alice Christian chr 01 Jan 1789
BANKS, Jane chr 24 May 1790
BANKS, Jno chr 19 Apr 1797

Matthias BANKS m Anne CASEMENT 24 may 1787, Onchan, IOM

Matthias BANCKS s/o Matthias BANCKS & Alice CHRISTIAN chr 13 Nov 1759, Onchan, IOM

Other offspring:

BANKS, William chr 13 Jun 1767 Onchan
BANCKS, Alice chr 08 Nov 1770 & 10 May 1780
BANCKS, Ellinor chr 03 Aug 1772
BANCKS, Isabel chr 03 Nov 1764
BANCKS, Jane chr 15 Nov 1761 (m George CALLOW 15 Jan 1799, Onchan, IOM)
See: http://genforum.genealogy.com/callow/
regarding George & Sylvester CALLOW

Matthias BANKS m Alice CHRISTIAN 03 Jun 1758, Onchan, IOM

BANCKES, Matthias s/o James BANCKES chr 18 Aug 1727, Onchan, IOM

James BANCKES m Isabel COTTINGHAM 28 Feb 1714, Onchan, IOM

Other children of James BANCKES (& Isabel ?):

Robert chr 02 oct 1740
James chr 18 mar 1715
Isabel chr 14 Apr 1718
Ann chr 08 May 1723, Lonan, IOM
Female chr 08 Jun 1720
Male chr 08 May 1725
William chr 08 may 1725 & 09 Dec 1729

The IGI also has the marriages & offspring of other siblings