By the time of the 1841 census, Auguste was back living in Guernsey and married again to Sophia (surname unknown). She must have died between 1851 and 1871. Most likely between 1851 and 1861. By 1871, Auguste had married again to Mary Judith Le Page, d/o James Le Page and Rachel Tabel (Rachel was my gt x 3 grandfather's sister).
1841: Commercial Arcade, St Peter Port, Guernsey
A B Goupillot 38 1803 Grocer France
S Goupillot 30 1811 Guernsey
Anne Goupillot 7 1834 Guernsey
L Goupillot 3 1838 Guernsey
Augustine Goupillot 2 1839 Guernsey
Judith Ozanne 16 1825 Servant Guernsey
George Dodd 17 1824 Servant Guernsey
1851: 2, St James Road Victoria Place, St Peters Port, Guernsey
Auguste Goupillot Head 48 1803 Grocer Employing 2 Men France
Sophia Goupillot Wife 40 1811 Domestic Duties St Peter Port, Guernsey
Ann Goupillot Dau 17 1834 - St Peter Port, Guernsey
Louisa Goupillot Dau 13 1838 Scholar St Peter Port, Guernsey
Augusta Goupillot Dau 11 1840 Scholar St Peter Port, Guernsey
Isabella Goupillot Dau 7 1844 Scholar St Peter Port, Guernsey
1861: 13, Fountain Street, St Peter Port, Guernsey
Auguste Goupillot Head 60 1801 Grocer Employing 3 Men France (British Subject)
Isabella Goupillot Dau 17 1844 House Keeper St Peter Port, Guernsey
Rosa Goupillot Dau 14 1847 House Keeper St Peter Port, Guernsey
Alfred Goupillot Son 12 1849 Scholar St Peter Port, Guernsey
Phidorah Goupillot Dau 9 1852 Scholar St Peter Port, Guernsey
Augustus Goupillot Son 7 1854 Scholar St Peter Port, Guernsey
Thomas Goupillot Son 6 1855 Scholar St Peter Port, Guernsey
Note: Auguste is recorded as Married but wife not with him.
1871: Fountain Street, St Peter Port, Guernsey
Auguste Goupillot Head 68 1803 Grocer employing 1 man France
Mary Goupillot Wife 40 1831 - Vale, Guernsey
Thomas Goupillot Son 18 1853 Seaman St Peter Port, Guernsey
Rachel le Page Mother-In-Law 69 1802 Annuitant St Peter Port, Guernsey
Rachel le Page Servant 45 1826 General Servant Domestic St Peter Port, Guernsey