Question: Who is Lord Herbert Montagu Douglas Scott's maternal grandfather?

Context paragraphs:
title: Elizabeth Percy, Duchess of Northumberland (born 1922)
paragraph_text: Elizabeth Diana Percy, Duchess of Northumberland( née Lady Elizabeth Montagu Douglas Scott; 20 January 1922 – 19 September 2012)
title: Charlotte Montagu Douglas Scott, Duchess of Buccleuch
paragraph_text: Charlotte Anne Montagu Douglas Scott, Duchess of Buccleuch and Queensberry, VA(" née" Thynne; 10 April 1811 – 18 March 1895) was a British peeress. A daughter of Thomas Thynne, 2nd Marquess of Bath, Charlotte married Walter Montagu Douglas Scott, 5th Duke of Buccleuch in 1829. They had seven children, including William Montagu Douglas Scott, 6th Duke of Buccleuch; Henry Douglas- Scott- Montagu, 1st Baron Montagu of Beaulieu; and the Royal Navy admiral Lord Charles Montagu Douglas Scott. From 1841 to 1846, the Duchess of Buccleuch served as the Mistress of the Robes to Queen Victoria as a member of Robert Peel's ministry. Her husband, a staunch Conservative, also served in Peel's ministry, and the Duchess used the connection to gain patronage for her brothers. She and the Queen remained lifelong friends, with the latter serving as godmother to Charlotte's daughter Lady Victoria. The Duchess advised her on Scotland, and later converted to Roman Catholicism in 1860. She engaged in philanthropic efforts in Scotland, and died in 1895 at Ditton Park.
title: Lord George Scott
paragraph_text: Lord George William Montagu Douglas Scott,( 31 August 1866 – 23 February 1947) was a Scottish cricketer and soldier. He was the brother of John Montagu Douglas Scott, 7th Duke of Buccleuch and the son of William Montagu Douglas Scott, 6th Duke of Buccleuch. Princess Alice, Duchess of Gloucester was his niece. Scott was born in Bowhill, Selkirkshire, the third son of William Montagu Douglas Scott, 6th Duke of Buccleuch. He was educated at Eton and Christ Church, Oxford. He played first- class cricket for various teams including Middlesex, Marylebone Cricket Club( MCC) and Oxford University from 1884 to 1905. He represented the Gentlemen in the Gentlemen v Players series. He was also Master of the Buccleuch Hunt. Scott was commissioned a second lieutenant in the 10th Hussars on 27 March 1889, was promoted to the rank of lieutenant on 11 June 1890, and to captain on 25 June 1897. He served in the Second Boer War, and left the regular army in August 1902. He later commanded the 2/1st Lothians and Border Horse, a Yeomanry( later Territorial Army) regiment, through World War I until January 1919 when he retired. He was appointed OBE in the 1919 Birthday Honours. He was a Deputy Lieutenant of Roxburghshire. In 1903, Scott married Lady Elizabeth Manners( died 1924), the youngest daughter of the John Manners, 7th Duke of Rutland. Together they had two sons and three daughters. His eldest daughter, Georgina Mary Scott, married Raymond O' Neill, 4th Baron O'Neill in 1963. He died in Melrose, Scottish Borders.
title: Walter Montagu Douglas Scott, 8th Duke of Buccleuch
paragraph_text: Walter John Montagu Douglas Scott, 8th Duke of Buccleuch and 10th Duke of Queensberry,( 30 December 1894 – 4 October 1973) was a Scottish peer and Conservative politician. He was the son of John Montagu Douglas Scott, 7th Duke of Buccleuch and Lady Margaret Alice" Molly" Bridgeman. His sister, Alice, married Prince Henry, Duke of Gloucester( one of the paternal uncles of Queen Elizabeth II) in 1935, becoming a member of the British Royal Family.
title: Andrew Montagu Douglas Scott
paragraph_text: Brigadier Claud Andrew Montagu Douglas Scott, DSO( 13 July 1906 – 24 January 1971) was the first child and only son born to Lieutenant Colonel Lord Herbert Andrew Montagu Douglas Scott and Marie Josephine Edwards. He was a grandson of Sir William Henry Walter Montagu Douglas Scott, 6th Duke of Buccleuch& 8th Duke of Queensberry and Lady Louisa Jane Hamilton, and a paternal first cousin to Lady Alice, Duchess of Gloucester, later known as Princess Alice, Duchess of Gloucester. He was a maternal first cousin once removed to Prince William of Gloucester and Prince Richard, Duke of Gloucester, a paternal great- uncle to Sarah, Duchess of York, and a maternal second great- uncle to Princesses Beatrice and Eugenie of York.
title: Lord Charles Montagu Douglas Scott
paragraph_text: Admiral Lord Charles Thomas Montagu Douglas Scott,( 20 October 1839 – 21 August 1911) was a Royal Navy officer who served as Commander- in- Chief, Plymouth.
title: Lord Herbert Montagu Douglas Scott
paragraph_text: Lieutenant- Colonel Lord Herbert Andrew Montagu Douglas Scott, CMG, DSO( 30 November 1872 – 17 June 1944) was the fifth child born to William Henry Walter Montagu Douglas Scott, 6th Duke of Buccleuch& 8th Duke of Queensberry and Lady Louisa Jane Hamilton. Lord Herbert Andrew was a great- grandfather to Sarah, Duchess of York, and a maternal second great- grandfather( great- great- grandfather) to Princess Beatrice of York and Princess Eugenie of York. He was also a paternal uncle of Princess Alice, Duchess of Gloucester, previously Lady Alice Montagu Douglas Scott, and thereby a maternal granduncle to Prince William of Gloucester and Prince Richard, Duke of Gloucester.
title: John Montagu Douglas Scott, 7th Duke of Buccleuch
paragraph_text: John Charles Montagu Douglas Scott, 7th Duke of Buccleuch and 9th Duke of Queensberry, (30 March 1864 – 19 October 1935), styled The Honourable John Montagu Douglas Scott until 1884, Lord John Montagu Douglas Scott between 1884 and 1886 and Earl of Dalkeith until 1914 was a Scottish Member of Parliament and peer.
title: Louisa Montagu Douglas Scott, Duchess of Buccleuch
paragraph_text: Louisa Jane Montagu Douglas Scott, Duchess of Buccleuch and Queensberry( 26 August 1836 – 16 March 1912) was the daughter of James Hamilton, 1st Duke of Abercorn. In 1884, she became the Duchess of Buccleuch and Duchess of Queensberry, the wife of William Henry Walter Montagu Douglas Scott, 6th Duke of Buccleuch& 8th Duke of Queensberry. She was the paternal grandmother of Princess Alice, Duchess of Gloucester and of Marian Louisa, Lady Elmhirst, as well as the maternal great- grandmother of Prince William of Gloucester, Prince Richard, Duke of Gloucester and great- great- grandmother of Sarah, Duchess of York.
title: Marian Montagu Douglas Scott
paragraph_text: Marian Louisa, Lady Elmhirst( previously Ferguson; née Montagu Douglas Scott; 16 June 1908 – 11 December 1996) was the first daughter born to Lord Herbert Montagu Douglas Scott and Marie Edwards. She was the paternal grandmother of Sarah, Duchess of York, and the maternal great- grandmother of Princesses Beatrice and Eugenie of York. Elmhirst was also a first cousin of Lady Alice Montagu Douglas Scott, who became the Duchess of Gloucester after her wedding to Prince Henry, and an aunt- by- marriage of Queen Elizabeth II.

Reasoning steps:
Herbert Andrew Montagu Douglas Scott mother Louisa Jane Hamilton
Louisa Jane Montagu Douglas Scott, Duchess of Buccleuch father James Hamilton

Answer: spans: James Hamilton