I am a descendant of the Seddon family. My Great Great Great Grandfather was James seddon b1821 and was the uncle of Richard John Seddon. James was the brother of Thomas Seddon b1817 who was RJS's father. Here is a list of Thomas's other brothers and sisters for anyone who needs them.
Edward Seddon b1818 d1898 married Julia Armstrong in 1858 William Seddon b1819 married Rachel Valentine in 1845 James Seddon b1821 d1869 married Margaret Aspinwall in 1847 Nathan Seddon b1822 married Mary Ann Smith in 1872 Jane Seddon b1825 married John Tyrer in 1847 John Seddon b1827 d1885 married Rosina Fishwick in 1868 Robert Seddon b1829 d1842 Ellen Seddon b1832 married Thomas Rothwell in 1855 Benjamin Seddon b1834 d1860 Richard Seddon b1835 d1898 married Mary Glover Stephen Seddon b1836 d1837 Stephen Seddon b1839
Their parents were George Seddon b1790 d1862 and Phoebe Prescott b1797 d1858. They married in 1816 in Upholland. George was born in Halsall and Phoebe in Ormskirk.
I have managed to trace the Seddons back to the 1700's and the Prescotts to the 1570's.
If anyone needs any more info you are welcome to e-mail me.