Hi Brenda
I think I have found you some info on Sarah Yates, it sound like you are right about Sarah being Jane's sister, Sarah was Christened 16th October 1814 in Maghull, Lancashire, Father Joseph and mother Martha, I have Jane Yates born 1826, 12 years later, Father Joseph Yates and mother Martha Garner, Joseph and Martha where married in Maghull, liverpool in 1813.
Regards Ivor