Hello Jill
I also cannot find your Jane Paterson, or her parents James, and Margaret, anywhere in Ayrshire.
However two of Janes, siblings Barbara, and Andrew Paterson, are living with what most likely is their mother Margaret Murdoch's, parents in Ochiltree, Ayr, in 1841.
Ochiltree Mill, Ochiltree, Ayr.
Andrew Murdoch, M. age 75 years, Mason, born Ayrshire,
Elizabeth Murdoch, F. age 80 years, born Ayrshire,
Barbara Paterson, F. age 15 years, born Ayrshire,
Andrew Paterson, M. age 10 years, born Ayrshire.
In case you dont have this information the above couple were married,
Andrew Murdoch, to Elizabeth Baird, 05/Jun/1784. Ochiltree, Ayr.
Their Daughter, Margaret Murdoch, was born 17/Dec/1819. Ochiltree, Ayr.
Margaret, married James Paterson, 20/Dec/1819. Ochiltree, Ayr.
Its possible by 1841. both James Paterson, and Margaret Murdoch, have died, and their children split up, or they have moved out of Ayrshire, and Barbara, and Andrew, have stayed with their Grandparents.
Regards,
Jonn.