Question:  Peter Shand Kydd was half-brother to the brother-in-law of a British peer suspected of murder who disappeared in what year?

Context paragraphs:
John Shand Kydd: John "Johnnie" Shand Kydd (born in 1959) is an internationally exhibited photographer, the youngest son of Peter Shand Kydd and Janet Munro Kerr, and the stepbrother to Diana, Princess of Wales.  Kydd has exhibited at the National Portrait Gallery.

Shand Kydd: Shand Kydd is an English surname.  It may refer to:

Frederick Hervey, 8th Marquess of Bristol: Frederick William Augustus Hervey, 8th Marquess of Bristol (born 19 October 1979) is a British peer.  He succeeded his elder half-brother the 7th Marquess (1954–1999) in January 1999 as Marquess of Bristol.  He is also the 12th Earl of Bristol, Earl Jermyn of Horningsheath in the County of Suffolk, 13th Baron Hervey of Ickworth in the County of Suffolk, and Hereditary High Steward of the Liberty of St Edmund, which encompasses the whole former county of West Suffolk.

Lady Sarah McCorquodale: Lady Elizabeth Sarah Lavinia McCorquodale (née Spencer; born 19 March 1955) is the eldest daughter of John Spencer, 8th Earl Spencer, and the Hon. Frances Shand Kydd.  She is the sister of Diana, Princess of Wales.

Lucan (2013 TV series): Lucan is a two part television film which debuted on ITV on 11 December 2013.  It stars Rory Kinnear as John Bingham, 7th Earl of Lucan (born 18 December 1934), popularly known as Lord Lucan, a British peer and suspected murderer, who disappeared without trace early on 8 November 1974.  The film was written by Jeff Pope and directed by Adrian Shergold.

Frances Shand Kydd: Frances Ruth Roche Shand Kydd (20 January 1936 – 3 June 2004) was the mother of Diana, Princess of Wales.  Her biographer, Max Riddington, who was the writer of "Frances: The Remarkable Story of Princess Diana's Mother", described Shand Kydd as a woman who was "certainly complicated" and also "funny, warm, intelligent, and energetic."  Following her divorce from Viscount Althorp in 1969, and Diana's death in 1997, Shand Kydd devoted the final years of her life to Roman Catholic charity work.

Archibald Acheson, 3rd Earl of Gosford: Archibald Acheson, 3rd Earl of Gosford KP (20 August 1806 – 15 June 1864), styled Viscount Acheson between 1807 and 1849, was a British peer.  The son of Archibald Acheson, 2nd Earl of Gosford, he succeeded to that Irish Earldom (and a British peerage) upon the death of his father in 1849, but had previously been created a British peer in his own right in 1847.

Peter Shand Kydd: Peter Shand Kydd (23 April 1925 – 23 March 2006) was the former stepfather of Diana, Princess of Wales, and an heir to the wallpaper fortune built by his father Norman Shand Kydd (1895–1962).  His mother was Francis Madalein Foy (died 1983).  He was half-brother to the former champion amateur jockey William Shand Kydd (1937–2014), who was brother-in-law of John Bingham, 7th Earl of Lucan.

British Peer (ship): The British Peer was a 1428-ton three-masted iron sailing ship built for the British Shipowners Company at the Harland and Wolff yards in Belfast, Ireland, in 1865.  She was 247.5 ft long, 36.4 ft wide and 22.5 ft deep.  She was bought by the Nourse Line in 1883, and was the fastest vessel in their fleet until the "British Ambassador" was commissioned.  In 1878, however, "British Peer"' s sailing power was compromised, when alterations were made to increase her tonnage by lengthening her hull by 32 ft , and she was never as fast again.  She carried a crew of 23, including her master.

John Bingham, 7th Earl of Lucan: Richard John Bingham, 7th Earl of Lucan (18 December 1934 – disappeared 7 November 1974), commonly known as Lord Lucan, was a British peer suspected of murder who disappeared in 1974.  He was born into an Anglo-Irish aristocratic family in Marylebone, the eldest son of George Bingham, 6th Earl of Lucan, by his marriage to Kaitlin Dawson.  An evacuee during the Second World War, Lucan returned to attend Eton College, and then from 1953 to 1955 served with the Coldstream Guards in West Germany.  He developed a taste for gambling and, skilled at backgammon and bridge, became an early member of the Clermont Club.  Although his losses often exceeded his winnings, he left his job at a London-based merchant bank and became a professional gambler.  He was known as Lord Bingham during his father's earldom from April 1949 until January 1964.

Supporting paragraphs: Peter Shand Kydd John Bingham, 7th Earl of Lucan
Answer: 1974