The Gatehouse website record of a licence to crenellate for Dedisham granted on 1329 Sept 30

Licence for Thomas Tregoz to crenellate his dwelling house of Dachesham, co. Sussex. By p.s. (CPR)

Thomas Tregoz ... mansum ... Dachesam, Sussex. (Turner and Parker)

The king to all &c., greeting – Know that of our special grace we have granted on behalf of ourselves and our heirs, to our beloved and faithful Thomas Tregoz, that he may fortify with a wall of stone and lime, and krenellate his manse of Dachesham, in the County of Sussex, and may hold that manse so fortified and krenellated, for himself and his heirs, for ever, without penalty or impediment from us, or our heirs, or our officers whatsoever. In witness whereof, &c. Witness the King at Worcester, on the 30th day of September. (Pat. 4 Edw. III., p.1 m.40) (Blaauw)

Granted at Worcester. Grant by privy seal.

Original source is;

Lyte, H.C. Maxwell (ed), 1891, Calendar of Patent Rolls (1327-30) p. 495 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;

Emery, Anthony, 2006, Greater Medieval Houses Vol. 3 (Cambridge) p. 439
King, D.J.C., 1983, Castellarium Anglicanum (London: Kraus) Vol. 2 p. 479n56
Blaauw, William Henry, 1861, ' Royal Licenses to Fortify Towns and Houses in Sussex' Sussex Archaeological Collections Vol. 13 p. 112 online copy
Turner, T.H. and Parker, J.H., 1859, Some account of Domestic Architecture in England (Oxford) Vol. 3 part 2 p. 409 online copy

Thomas Tregoz (d. 1335)

Tregoz seems to be held, as a subtenant to Robert Tateshale, a few manors in Sussex but to be otherwise an undistinguished person. John de Tregoz was created Lord Tregoz in 1299 and Thomas in some genealogies appears to be his grandson, sometimes described him as 3rd Baron Tregoz, however other genealogies give a different, more distant connection. It appears he had no claim to the Tregoz family holdings in the welsh marches.
Thomas was appointed to organise and lead contingents against the Scots from Sussex, 1316, 1322, and 1323, and from Surrey and Sussex in 1326, and further summoned for personal service against the Scots 1318, 1319, 1333, 1nd 1335...As if to underline that, Thomas de Tregoz was a knight of great note; he was certified, pursuant to a writ tested at Clipstone, to be Lord of Goring, Preston, Burpham, and Greatham, Sussex... Thomas de Tregoz was appointed Knight of the Shire for Sussex, 1320 and 1321... Thomas de Tregoz, being returned by the Sheriff of Sussex to attend the Great Council at Westminster. Thomas de Tregoz was Justice for oyer and terminer in Kent, Surrey, Sussex, Hants and Wilts. He was again summoned for Parliament as a Baron, from 27 Jan 1331/2 to 1 April 1335. (Symond)

Although summoned to parliament by writ in 1317 (the parliament was prorogued) and 1331 Thomas also served as knight of the shire for Sussex. The family were clearly on the cusp of baronial status.

Biographical source include;

'wasfu-man' (Richard Symond), 2007 June 23, 'Dedisham manor, Slinford' http://wasfu-man-dedishamhistory.blogspot.com/ (A blog by a professional archaeologist)