Sources

1) Source: Chancery: Inquisitions Post Mortem, Series I, Henry III "Adam de Puriton...Robert de Kaynes son of Sir William de Kaynes, who is in the king s wardship, is one of the heirs of the said Adam, having been born of Margery his eldest daughter, and was 16 years of age at the feast of the Annunciation, 50 Henry III."Dated: 1265/6. External Link
https://www.british-history.ac.uk/inquis-post-mortem/vol13/pp273-276. Reference: C 132/33/7, E. Enrolments &c. of Inq. No. 571 (Data from secondary evidence)
2) Source: Special Collections: Ancient Petitions "Hawise, widow of Robert de Kaynes, states that a knight's fee in Lasborough was assigned to her as dower after the death of her husband"Date: c1328. External Link
http://discovery.nationalarchives.gov.uk/details/r/C9060929. Reference: SC 8/16/788 (Data from direct source)
3) Source: Court of Chancery: Six Clerks Office: Early Proceedings, Richard II to Philip and Mary "Plaintiffs: Thomas Chaworth, knt. and Isabel his wife, and Eleanor, late the wife of Humphrey Stafford, knt. of Grafton, daughters of Thomas Aylesbury, knt., descendant and heir of Hawise Kaynes." Hawise de Keynes was Eleanor's Great-Great-Great Grandfather.Dated: 1454 Hawise de Keynes was Eleanor's Great-Great-Great Grandfather!. External Link
http://discovery.nationalarchives.gov.uk/details/r/C7441321. Reference: C 1/24/51 (Data from secondary evidence)
4) Source: Special Collections: Ancient Petitions "Hawise, widow of Robert de Kaynes, states that a knight's fee in Lasborough was assigned to her as dower after the death of her husband"Date: c1328 Evidences that Robert's wife was Hawise.. External Link
http://discovery.nationalarchives.gov.uk/details/r/C9060929. Reference: SC 8/16/788 (Data from secondary evidence)
5) Source: Chancery: Inquisitions Post Mortem, Series I, Edward III "Philip de Aylesbury...ohn Thurbern, chaplain, who granted it to the said Philip and Margaret for their lives by fine in the king’s court, with remainder to Thomas their son and his heirs. The said Thomas died in the lifetime of Philip and so, after the said Philip’s death, the manor should remain to John son of the said Thomas and his heirs. ...He died on 14 July last. John son of the aforesaid Thomas, aged 13 years and more..."Dated: 1349. External Link
https://www.british-history.ac.uk/inquis-post-mortem/vol9/pp328-367. Reference: C 135/106/2 (Data from direct source)