Hello Sue,
I was intrigued to see that we share some ancestors in common.
Elizabeth Lisle was married to my g g grandfather, William Lisle. After years of search I found this marriage as a irregular marriage at Starch House Toll.
They do not appear on the 1851 census because they didn't marry until 1852. William was a widowerer.
If you want to know more, do reply.
Best wishes