Having found out who my grandfather Harry Carr-Brion really was I decided to take a DNA test to prove it. The results came back and showed I am definitely related to the Kingwell family. It also found a second cousin who I knew nothing about and lots of Scottish ancestors I knew nothing about. Looking carefully I have found DNA links to every main branch of my family tree except for the Mann and the Caswell families, who should have been my other grandfather's ancestors. It appears my other grandfather was not who we thought he was.

This led me to a family in Scotland. Comparing the family to my grandfather's family showed some strange similarities.

John Douglas Gunn (Teacher on Skye) born 5 Apr 1861, Bower, Caithness
John Douglas Gunn and Mary McLean married 10 Oct 1883, Inverness
Andrew Rugg-Gunn (Eye surgeon) born 26 Nov 1884, Lochbroom, Ross-shire
Isabella Gunn, born 16 Apr 1886, Lochbroom, Ross-shire
Elizabeth Maud Gunn born 23 Feb 1888, Kyleakin, Skye
Alexander John Gunn (Died during WW1) born 6 Sep 1889, Kyleakin, Skye
Dorothea Rachel Gunn (Teacher) born 26 Dec 1890, Kyleakin, Skye

William Clarence Herbert Mann born 5 Apr 1865, Plymouth, Devon
William Clarence Herbert Mann and Elizabeth Anne Casswell married 23 Aug 1893, West Norwood, London
Herbert Clarence Mann (Lecturer in electrical engineering) born 26 Nov 1894
Frederick George Mann (Chemist at Trinity College, Cambridge) born 29 Jun 1897 (My grandfather)
Mildred Kate Mann born 2 Feb 1900
Phyllis Mary Mann born 11 Apr 1906

Mann and Gunn are two similar surnames. Also, the birthdays of the two fathers and the two eldest children are the same but a few years apart. The probability of this being chance is about 1 in 133,000. DNA tests show the descendants of Herbert Clarence Mann are from the Mann family and the descendants of Frederick George Mann are from the Gunn family. DNA testing links me and my first cousins to the ancestors of both John Douglas Gunn and Mary McLean. This gives two options:

A more recent DNA test has shown me to be more closely related to the descendants of Andrew Rugg-Gunn. This suggests that Andrew Rugg-Gunn is my genetic grandfather.

If anyone has any information that would help explain this then I would be most interested.