Lady Eleanor Neville was the 2nd daughter of Ralph Neville, Earl of Westmorland by his 2nd wife, Joan Beaufort, daughter of John of Gaunt, Duke of Lancaster and his 3rd wife, Katharine Swynford.
She was married first to Richard le Despenser, 4th Baron Burghersh, (a grandson of Gaunt's younger brother Edmund of York), and after his early death without child, she married Henry Percy, 2nd Earl of Northumberland (killed at the first battle of St Albans, 1455).
Eleanor and Henry had 10 children, including:
Henry Percy, 3rd Earl of Northumberland (25 July 1421 - 29 March 1461, Battle of Towton).
Lady Katherine Percy. She married Edmund Grey, 1st Earl of Kent
Thomas Percy, 1st Baron Egremont (29 November 1422, Leconfield, Yorkshire - 10 July 1460 Battle of Northampton, England)
Sir Ralph Percy (d. 25 April 1464, Battle of Hedgeley Moor).
The will of her son George Percy (died 1474) proves beyond a doubt she is buried in Beverley Minster. (burial info from Todd Whitesides)
conflicting burial info
This does not prove 'beyond any doubt' that Eleanor Neville was buried at Beverley. There was another Eleanor Percy buried at Beverley, in the north aisle, in 1328 whose memorial still exists. Eleanor Neville died in Durham so was more likely to have been buried at Staindrop near the family seat at Raby Castle, although I can not confirm that as fact.
It is only her son George's will which indicates that he was buried in the north aisle of Beverley Minster, which he was, as indicated by the visit and description by John Leland in 1541. His will states, "Sep. infra ecclesiam collegiatam B. Johannis Beveraci, insula boriali ejusdem, juxta tumulum dominae Elionorae Percy." However, we know that Eleanor Percy, wife of the Henry 1st Baron Percy was buried in the Minster in 1328, but as far as I know, Eleanor Neville, George's mother was not. It is therefore likely that the 'lady Eleanor' (dominae Elionorae) mentioned in his will was his 4x great grandmother, and not his mother. I am a historian working on Beverley Minster, and the Percy burials, and am a friend of the Alnwick castle archivist, so I am confident that the current situation regarding Eleanor Neville is as outlined above. Any update will be posted on this site as information becomes available.
Information from Jrp25
Katherine Neville Woodville
Robert de Neville
William de Neville
George Neville, Lord Latimer
Anne de Neville Stafford
Edward Neville, 1st Lord Abergavenny
Cecily de Neville Plantagenet