Hi Lois
The following looks like your Mary
Mary Saich born 10 Apr 1790, bapt 9 May 1790 Ruislip. She married William Mathews (born Hillingdon 1795) at Christchurch Newgate 6 June 1815 and died at her brother Matthew’s home in Paddington 27 Mar 1849 being buried in Woolwich 1 Apr 1849.
She is part of the Ruislip family which I can take back to around 1700.
David Wilson