Hi FidgettFerret,
Yes, you are right that it is a mystery. The reason I started researching this family is that the child (Eliza Maud Peacock) on the 1881/91 Census was my grandmother who did a "disappearing act" on three very small little girls, one of whom was my mother. I was pleased to find the family and yes, my mother and one of her sisters was born in Harwich.
I then started investigating Rebecca and George Peacock. You are right, Rebecca was a Cooper from Chelmondiston, near Ipswich and the family had lived there for some generations.
Because Rebecca appeared as a widow on the 1891 Census as a widow in Ipswich I then started to research George's death but have never been able to find it.
I then moved sideways and found grandchildren of sisters who have given me masses of information including informing me that the three young boys on the 1891 Census were called Fidgett.
I have a birth certificate for Thomas Charles b. 1882 whose father was Thomas a labourer and at the time they were living at 3. Lower Orwell Street, Ipswich.
I have a death certificate for Victor Fidgett Peacock, d. 1892 at George Street, Harwich, aged 4 and it says he was the son of John Peacock, a Journeyman Miller, mother, Rebecca Peacock.
Your guess is as good as mine!
I could not trace the 1901 Census but I found the 1911 Census and Rebecca Peacock was living in Greenwich. She then died in the Union Infrmary in 1918 in Greenwich.
I welcome your interest and hope you understand all this.
Goldbar