I have done a little research here into this John Duck and Emma Talbot but they married 1865 in Kingsbury Episcopi, Elizabeth surely can't be their child. However, John is described as being a widow, so maybe he married way before to Elizabeth's mother?

John's father is described as a John Duck, who possibly married a Jane Knight in 1841. Or was it John Duck who married Emma Talbot that married Jane Knight, because that would be before Elizabeth's birth date.

However, there is still no baptism for Elizabeth.