William Montagu Douglas Scott, 6th Duke of Buccleuch
William Henry Walter Montagu Douglas Scott, 6th Duke of Buccleuch and 8th Duke of Queensberry( 9 September 1831 – 5 November 1914) was a Scottish Member of Parliament and peer.
He was the paternal grandfather of Princess Alice, Duchess of Gloucester, and the maternal great- grandfather of Prince William of Gloucester and Prince Richard, Duke of Gloucester.
He was a paternal great- great- grandfather to Sarah, Duchess of York.
John Jones (MP for Gloucester)
John Jones (died 1 June 1630) was an English politician who sat in the House of Commons from 1604 to 1611.
Jones was the son of Hugh Joanes of Milton, Gloucestershire.
From before 1579, he was the Principal Registrar of the diocese of Gloucester covering the time of eight Bishops of Gloucester from Richard Cheyney to Godfrey Goodman.
He was an alderman of Gloucester and was Sheriff of Gloucester in 1587 and 1592 and Mayor of Gloucester in 1597.
He was also J.P. for the City.
In 1604, he was elected Member of Parliament for Gloucester.
He was mayor of Gloucester again in 1618 and 1625.
Jones died in 1630 and was buried in Gloucester Cathedral.
Jones married firstly Joane Huntley widow born as Weale.
She died on 18 January 1595 and he married secondly Elizabeth Gilbert daughter of J. Gilbert of Clare, Suffolk.
William Fitz Robert, 2nd Earl of Gloucester
William Fitz Robert, 2nd Earl of Gloucester( 23 November 1116 – 23 November 1183) was the son and heir of Sir Robert de Caen, 1st Earl of Gloucester, and Mabel FitzRobert of Gloucester, daughter of Robert Fitzhamon and nephew of Empress Matilda.
Anthony Robinson (MP)
Anthony Robinson( born 1592) was an English politician who sat in the House of Commons in 1621 and 1624.
Robinson was the son of Robert Robinson of Gloucester.
He matriculated at St Alban Hall, Oxford on 14 October 1597, aged 15, and in 1601 entered the Middle Temple to study law.
He was sheriff of Gloucester in 1616.
In 1621, he was elected Member of Parliament for Gloucester and re-elected MP in 1624.
In 1626 he was made an alderman for life and in 1629 he was made Mayor of Gloucester for a year.
He married Hester, daughter of John Browne, mercer of Gloucester, and had 6 sons and 3 daughters.
Henry Scott, 3rd Duke of Buccleuch
Henry Scott, 3rd Duke of Buccleuch and 5th Duke of Queensberry KG FRSE( 2 September 174611 January 1812) was a Scottish nobleman and long- time friend of Sir Walter Scott.
He is the paternal 3rd great- grandfather of Princess Alice, Duchess of Gloucester, and the maternal 4th great- grandfather of Prince William of Gloucester and Prince Richard, Duke of Gloucester.
Much of the family's lands and wealth were accumulated during Henry's tenure as Duke.
He integrated the surnames" Montagu" and" Douglas" with the Scott family name to form the unhyphenated compound surname" Montagu Douglas Scott".
Miles of Gloucester, 1st Earl of Hereford
Miles FitzWalter of Gloucester, 1st Earl of Hereford, Lord of Brecknock( died 24 December 1143) was High Sheriff of Gloucester and Constable of England.
Anne of Gloucester
Anne of Gloucester, Countess of Stafford (30 April 1383 – 16 October 1438) was the eldest daughter of Thomas of Woodstock, Duke of Gloucester, and Eleanor de Bohun.
Isabella of Gloucester and Hertford
Isabella de Clare (2 November 1226 – 10 July 1264) was the daughter of Gilbert de Clare, 4th Earl of Hertford and 5th Earl of Gloucester and Isabel Marshal.
She is also known as "Isabel de Clare", but this is however, the name of many women in her family.
Robert Payne (Gloucester MP)
Robert Payne( c. 1630 – 1713), of Gloucester, was an English politician.
He was the eldest son of Robert Payne of Gloucester, a clothier.
He was made a freeman of Gloucester in 1653, an alderman in 1679 and made mayor for 1692 and 1703.
He was a Member( MP) of the Parliament of England for Gloucester from 1695 to 1698.
He married Anna, the daughter of William Capel of Gloucester, and had 5 sons and 2 daughters.
Gilbert de Clare, 5th Earl of Gloucester
Gilbert de Clare, 4th Earl of Hertford, 5th Earl of Gloucester, 1st Lord of Glamorgan, 7th Lord of Clare (1180 – 25 October 1230) was the son of Richard de Clare, 3rd Earl of Hertford (c. 1153–1217), from whom he inherited the Clare estates.
He also inherited from his mother, Amice Fitz William, the estates of Gloucester and the honour of St. Hilary, and from Rohese, an ancestor, the moiety of the Giffard estates.
In June 1202, he was entrusted with the lands of Harfleur and Montrevillers.

Question: Who is Isabella Of Gloucester And Hertford's paternal grandfather?
Answer: Richard de Clare, 3rd Earl of Hertford