The Gatehouse website record of a licence to crenellate for Whitwick Castle granted on 1321 March 12

In 1321 March 12, Henricus de Bello Monte, Consanguineus Regis (Sir Henry de Beaumont) was granted, by Edward II, (In year 14 of his reign) a Royal licence to crenellate Whitewyk (Whitwick Castle)

Granted at Henley. Grant by privy seal.

Comments

The building resulting from this licence may have provoked the attack by Sir John Talbot. Beaumont claim to the land was from wife's inheritance and, it seems, Talbot felt he had a claim to Whitwick.

Original source is;

Lyte, H.C. Maxwell (ed), 1903, Calendar of Patent Rolls (1317-21) p. 571 online copy

(In fact, the original source given is usually a transcription/translation of what are precious medieval documents not readily availably. It should be noted that these transcription/translations often date to the nineteenth or early twentieth centuries and that unwitting bias of transcribers may affect the translation. Care should also be taken to avoid giving modern meaning to the medieval use of certain stock words and terms. Licentia is best translated as 'freedom to' not 'permission'.)

Significant later sources are;

Coulson, C., 1994, 'Freedom to Crenellate by Licence - An Historiographical Revision' Nottingham Medieval Studies Vol. 38 p. 120-1
King, D.J.C., 1983, Castellarium Anglicanum (London: Kraus) Vol. 1 p. 258n23
Turner, T.H. and Parker, J.H., 1859, Some account of Domestic Architecture in England (Oxford) Vol. 3 part 2 p. 408 online copy

Beaumont, Sir Henry de (c.1280–1340)

Joint warden of Scotland in 1308, he was summoned to parliament in 1309, and went on to receive extensive lands in Lincolnshire (augmented by his sister's lands in that county after her death in 1334) and the more contentious grant of the Isle of Man. The king's favour made him the special target of the reforming lords ordainer, who in 1311 called for the exclusion from court of both Beaumont and Isabella, the resumption of his grants from the king, and the transference of the custody of Man to ‘a good Englishman’ (a phrase that reveals one reason for his unpopularity). These demands, however, were never implemented and Beaumont remained prominent at Edward's court until 1323. (Maddicott)

Although specifically called a royal relative Henry was only a distant relative to Queen Eleanor, wife of Edward I. He was the younger son of a French vicomte but became a knight in the service of Edward I and joint warden of Scotland under Edward II and was prominent in Edward's court at the time of this licence.

Biographical source include;

J. R. Maddicott, 2004, ‘Beaumont, Sir Henry de (c.1280–1340)’ Oxford Dictionary of National Biography (Oxford University Press) online copy (subscription may be needed)