Have you traced Frederick George Barfoot back from 1881 census could he have been married and not free to marry Fanny
Frederick George BARFOOT was baptised 25 July 1851 at Great Canford, Dorset, his mother Elizabeth Mary BARFOOT, single woman. Birth registered Poole (8/67) no mmn.
Elizabeth Mary BARFOOT married Frederick DUKE 4 Nov 1851 at Great Canford (she was underage and illegitimate too). Interestingly in the 1851 census Elizabeth Mary and her mother Amelia BARFOOT are visitors with Frederick DUKE at Corfe Hills, Canford.
As noted back at the beginning of the thread, Frederick and Elizabeth Mary DUKE baptise 4 children with surname DUKE in 1859, plus Frederick George BARFOOT on the same day - so he seems to have been baptised twice.
Frederick George BARFOOT can be found in the 1861 and 1871 census with Frederick and Elizabeth Mary DUKE in Canford (as Frederick G DUKE in 1861 and George DUKE in 1871).
So there is 7 years between 1871 census in Canford and 1878 in Melton Mowbray where his first son(s) were born and died.
There is this mention of a Frederick George BARFOOT in 1875, in Snow Hill, London. Uncertain whether it is your F G BARFOOT. There is another Frederick George BARFOOT who married Elizabeth Azel SIMS 20 March 1870 at St Bride, Fleet St.
Publication: "The Hour"
Wednesday, 30 June 1875