Was your Janet born in Scotland ? If so I think that this couldbe her on the 1851 living in Bermondsey, mispselt as Janit dob given as 1791. Master mariners widow
Ancestry shows just one person living with her Agness Clarke mariners wife born Scotland described as sister in law.
Looking at the original document it looks like there is another two with them although their names are hard to read.
Looks like Jessie Shepherd age 30 b Scotland master mariners wife and Jessie S Shepherd age 5month daughter b Bermondsay.