Hi Diney,
Just checked
www.familysearch.org re this family.
All the info you have quoted is from a submitted ancestral file to the site.
This means someone has searched this family either in person or thru someone else.
From what I can see there is another possibility for Janes date of birth, with same parents from EXTRACTED records, that is ones taken from parish records.
You can check this out yourself.
Jane Grundy, the one I have found, born 18 June 1820, Little Lever, Lancs has lots of siblings from extracted records.
See what you think and I will look around more.
trish