Sources

1) Source: The History of Parliament . External Link
http://www.historyofparliamentonline.org/volume/1386-1421/member/russell-sir-maurice-1356-1416. Reference: Russell, Sir Maurice (1356-1416), of Kingston Russell, Dorset, Horsington, Som. and Dyrham, Glos. (Questionable reliability of evidence)
2) Source: Chancery: Inquisitions Post Mortem, Series I, Henry V "Drayton, John, kt... by their deed, dated at Dyrham on 27 Sept. 1400 and also shown, granted them to Thomas de la Ryvere, Isabel his wife and the heirs of their bodies, with remainder to Thomas and his heirs. They had issue Maurice. Thomas died and John Drayton, knight, married Isabel. He died holding the manors in right of Isabel...Ralph Russell, knight, held the manor and advowson of Dyrham...and by his deed, dated at Romsey on 19 Aug. 1369, granted it to Maurice his son and Isabel, Maurice’s wife, daughter of Edmund de Chelreye...Maurice and Isabel had issue Margaret now wife of Gilbert Denys, knight, and Isabel late the wife of John Drayton. Maurice and Isabel died, and half the manor descended to each of their daughters. John Drayton died holding half in right of Isabel...He died on 3 Oct. last. Joan and Elizabeth are his daughters and heirs, aged 8 years and more and 5 years and more."Dated: 1417. External Link
https://www.british-history.ac.uk/inquis-post-mortem/vol20/pp234-248. Reference: C 138/27/43 (Data from direct source)
3) Source: The visitation of the county of Gloucester, taken in the year 1623 Dennis. Reference: 49-51 (Questionable reliability of evidence)