Helen Mercedes Graves-Johnston1
Hon. Mary Cecilia Whitelaw1
From 1972, her married name became Coltman.
Child of Hon. Mary Cecilia Whitelaw and David Alexander Coltman
- Susannah Mary Lavinia Coltman3 b. 1987
David Alexander Coltman1 
He was educated at Eton College, Windsor, Berkshire, England.2 He was educated at Edinburgh University, Edinburgh, Midlothian, Scotland.2 He was chief executive of British Caledonian Airways.4 He lived in 2003 at Haystoun House, Peebles-shire, ScotlandG.2
Child of David Alexander Coltman and Hon. Mary Cecilia Whitelaw
- Susannah Mary Lavinia Coltman3 b. 1987
- [S8] BP1999 volume 2, page 3004. See link for full details for this source. Hereinafter cited as. [S8]
- [S37] BP2003 volume 2, page 1978. See link for full details for this source. Hereinafter cited as. [S37]
- [S37] BP2003. [S37]
- [S466] Notices, The Telegraph, London, UK. Hereinafter cited as The Telegraph.
Hon. Pamela Winifred Whitelaw1
From 27 April 1974, her married name became Graham.
Children of Hon. Pamela Winifred Whitelaw and Malise Charles Richard Graham
- Arabella Mary Susan Graham3 b. 19 May 1975
- Georgina Carol Cecilia Graham3 b. 19 Sep 1977
- Laura Meliora Winifred Graham3 b. 1981
- Victoria Malise Samantha Graham3 b. 1985
Kenneth Augustus Muir Mackenzie, 1st and last Baron Muir Mackenzie1 
He was educated at Charterhouse School, Godalming, Surrey, EnglandG.1 He graduated from Balliol College, Oxford University, Oxford, Oxfordshire, EnglandG, in 1868 with a Bachelor of Arts (B.A.)1 He was admitted to Lincoln’s Inn in 1873 entitled to practise as a Barrister-at-Law.1 He graduated from Balliol College, Oxford University, Oxford, Oxfordshire, EnglandG, in 1873 with a Master of Arts (M.A.)1 He was Clerk to the Crown in Treasury between 1885 and 1915.1 He was appointed Queen’s Counsel (Q.C.) in 1887.1 He was Permanent Secretary to the Lord Chancellor between 1890 and 1915.1 He held the office of Bencher of Lincoln’s Inn in 1891.1 He was appointed Companion, Order of the Bath (C.B.) in 1893.1 He was appointed Knight Commander, Order of the Bath (K.C.B.) in 1898.1 He held the office of Justice of the Peace (J.P.) for London.4 He was Warden of Winchester College between 1904 and 1915.4 He was appointed Knight Grand Cross, Order of the Bath (G.C.B.) in 1911.1 He held the office of High Bailiff of Westminster between 1912 and 1930.4 He was created 1st Baron Muir Mackenzie, of Delvine, co. Perth [U.K.] on 29 June 1915.1 He was appointed Privy Counsellor (P.C.) in 1924.1 On his death, his title became extinct.1
Children of Kenneth Augustus Muir Mackenzie, 1st and last Baron Muir Mackenzie and Amelia Graham
- William Montague Muir Mackenzie1 b. 12 May 1876, d. 18 Jul 1901
- Hon. Margaret Mary Muir Mackenzie1 b. 29 May 1879, d. 10 Aug 1958
- Hon. Dorothea Frances Muir Mackenzie+1 b. 4 Apr 1881
- Hon. Magdalen Muir Mackenzie+1 b. 26 Apr 1884, d. 14 Oct 1971
- [S21] L. G. Pine, The New Extinct Peerage 1884-1971: Containing Extinct, Abeyant, Dormant and Suspended Peerages With Genealogies and Arms (London, U.K.: Heraldry Today, 1972), page 202. Hereinafter cited as The New Extinct Peerage.
- [S37] BP2003 See link for full details for this source. Hereinafter cited as. [S37]
- [S3508] S. Thomson, “email: Kirwan Family,” e-mail message to BENR, 16 January 2009 – 12 February 2010. Hereinafter cited as “email: Kirwan Family.”
- [S37] BP2003. [S37]
Amelia Graham1 
From 26 February 1874, her married name became Muir Mackenzie.1
Children of Amelia Graham and Kenneth Augustus Muir Mackenzie, 1st and last Baron Muir Mackenzie
- William Montague Muir Mackenzie1 b. 12 May 1876, d. 18 Jul 1901
- Hon. Margaret Mary Muir Mackenzie1 b. 29 May 1879, d. 10 Aug 1958
- Hon. Dorothea Frances Muir Mackenzie+1 b. 4 Apr 1881
- Hon. Magdalen Muir Mackenzie+1 b. 26 Apr 1884, d. 14 Oct 1971
- [S21] L. G. Pine, The New Extinct Peerage 1884-1971: Containing Extinct, Abeyant, Dormant and Suspended Peerages With Genealogies and Arms (London, U.K.: Heraldry Today, 1972), page 202. Hereinafter cited as The New Extinct Peerage.
William Graham1
Child of William Graham
- Amelia Graham+1 d. 18 Dec 1900
- [S21] L. G. Pine, The New Extinct Peerage 1884-1971: Containing Extinct, Abeyant, Dormant and Suspended Peerages With Genealogies and Arms (London, U.K.: Heraldry Today, 1972), page 202. Hereinafter cited as The New Extinct Peerage.
- [S37] BP2003 volume 2, page 2826. See link for full details for this source. Hereinafter cited as. [S37]
William Montague Muir Mackenzie1 
He was a practising Barrister-at-Law.1
- [S21] L. G. Pine, The New Extinct Peerage 1884-1971: Containing Extinct, Abeyant, Dormant and Suspended Peerages With Genealogies and Arms (London, U.K.: Heraldry Today, 1972), page 202. Hereinafter cited as The New Extinct Peerage.
Hon. Margaret Mary Muir Mackenzie1 
From 3 January 1907, her married name became Post.1
- [S21] L. G. Pine, The New Extinct Peerage 1884-1971: Containing Extinct, Abeyant, Dormant and Suspended Peerages With Genealogies and Arms (London, U.K.: Heraldry Today, 1972), page 202. Hereinafter cited as The New Extinct Peerage.