Just adding this with a note of amusement and frustration. The last paragraph says it all.
Quoting from R.D Peacock's research,
6.2 The Dixons of Rothbury and Netherton
This Dixon family first appears with a fair degree of probability in the Registers of the Chapelry of Netherwitton, Northumberland, in 1765, though there is just a possibility that a marriage at Longframlington in 1744 between a James Dixon and an Elizabeth Handyside refers to the same family. Matthew Dixon, son of James & Elizabeth Dixon, was born at Birkhead in the Rothbury Forest, now merely a building but then possibly a small hamlet where quarrymen and 'open cast' miners lived (there was a quarry there in 1719). Matthew Dixon could certainly sign his name, and on the baptismal records of his children in Rothbury early in the 19thC he is shown as being a collier.
The name Rankin is Scottish (see under The Rankins of Lowick). Isobel was probably the daughter of the Robert Rankin and Isobel Reavley who were married in Eglingham in 1771, which leaves room for so far unknown brothers and sisters. The name 'Isobel', Isabel', or 'Isabella' became a family name associated with the Swanns (Aunt Adeline was the latest). For the Pigdons see the Pigdon Notes.
Clearly, the Swan(n)s never anticipated that later generations would be trying to unpick their line of descent in adopting this naming convention.