I stumbled across this old thread while looking for one of my own TOGG3 threads and couldn't resist having a dig
There's a death for Jane Sheldrick Q4 1874 at St Saviour, age 74 so the right age to be the Jane Sheldrick on the 1851 census. Could you get the death cert. to see who the informant was in case it's your Joseph?
Also a likely marriage for her - William Sheldrick and Jane Simmons, Lambeth St Mary 1824. One of the witnesses is ESTHER Sexton?? I'm not sure whether that's significant or not!