Susan Petronella Carbutt1 
From 14 July 1954, her married name became Guinness.
Children of Susan Petronella Carbutt and Anthony Peter Boothby Guinness
- Christopher Jens Guinness3 b. 30 Aug 1957, d. 9 Oct 1992
- Lucinda Claire Guinness3 b. 1 Apr 1959
Christopher Jens Guinness1 
He was educated at Shiplake College, Henley-on-Thames, Oxfordshire, EnglandG.1
Lucinda Claire Guinness1
John Henry Guinness1 
He was educated at Eton College, Windsor, Berkshire, EnglandG.1 He gained the rank of officer in the Royal Navy.1 He was a director of Guinness Peat Group, Heiton McFerran, Irish Shoe Supplies, McNeill Group and Telectron.1 He was chairman of Guinness Mahon.1
Children of John Henry Guinness and Mary Jennifer Hollwey
- Ian Richard Guinness+2 b. 15 Mar 1961
- Gillian Sarah Guinness2 b. 8 Jul 1962
- Tania Caroline Guinness2 b. 10 Feb 1966
Lt.-Col. James Bell Hollwey1,2 
He lived at Cabinteely, County Dublin, IrelandG.1
Child of Lt.-Col. James Bell Hollwey
- Mary Jennifer Hollwey+3 d. 23 Jan 2016
Mary Jennifer Hollwey1 
Mary Jennifer Hollwey usually went by her middle name of Jennifer.3 From 9 April 1959, her married name became Guinness. In April 1986 she was kidnapped, and rescued by armed police with no ransom paid.3 She lived in 2003 at Censure House, Ceanchor Road, Baily, County Dublin, IrelandG.1
Children of Mary Jennifer Hollwey and John Henry Guinness
- Ian Richard Guinness+2 b. 15 Mar 1961
- Gillian Sarah Guinness2 b. 8 Jul 1962
- Tania Caroline Guinness2 b. 10 Feb 1966
Ian Richard Guinness1
Children of Ian Richard Guinness and Mary Paula Diggin
- Henry Christopher Guinness3 b. 1990
- Frederick Peter Guinness3 b. 1991
- Freya Mary Guinness3 b. 1994
- Imogen Mary Guinness3 b. 1997
Mary Paula Diggin1
From 1987, her married name became Guinness.
Children of Mary Paula Diggin and Ian Richard Guinness
- Henry Christopher Guinness2 b. 1990
- Frederick Peter Guinness2 b. 1991
- Freya Mary Guinness2 b. 1994
- Imogen Mary Guinness2 b. 1997
Henry Christopher Guinness1
Frederick Peter Guinness1
