Hi. Frances
Ref. Margaret (Redfern) Bridson
Doc. http://junior.apk.net/~ctd/d0000/g0000053.html
Confirms your findings but gives her birth date as 1818 and you have placed her in the wrong family group in the family tree. By your findings and this Doc. Margaret is my g grandfathers older sister. Her husband William could be my grandmothers brother and as he was an Ironmonger this could be why my grandfather took up this profession.

Regards Richard Redfern NSW Aust.