Hi Tina,
I think the kids are correct, I think Thomas born 1798 was the brother of William who was a famous chemist, the other information comes from another person who is also researching the same family line, I will contact them and try and put them in contact with you, I have to use the Ancestery contact service.
I have checked Ann's marriage and you are correct, I think she may also have a sister Mary born to the same parents in the same place and the same timeline.
I will check it out
Brendan