His father died in 1850 and his mother remarried; to George Lee Gallon in 1851.
In 1861 William was living in West Derby with his mother, stepfather and siblings.[2]
Sources
↑Birth Registration England & Wales General Register Office, GRO Online Index - Birth (https://www.gro.gov.uk/gro/content/certificates/indexes_search.asp database entry for SEDDON, WILLIAM Mother's maiden surname: HALEWOOD ), GRO Reference: 1845 D Quarter in WEST DERBY Volume 20 Page 1037