W Gill had this to say in 3rd manx Scrapbook
(see www.manxnotebook.com/fulltext/scrap3/ch01.htm )
Among the names ending in "son" there is one at least of which the English aspect may belie it. Brydson — spelt Brideson, as it is still pronounced — appears several times in the Malew Abbey Rent Roll or Computus of 1540-41 ; see Cumming's Rushen Castle, Appendix B. Brydson is a signature to an Agreement in 1601. It does not occur in the Manorial Roll at the beginning of the 16th century, but MacGilbrid (" Son of Brigid's Servant ") is found among the entries for Andreas. Bridson, however, belongs to the South side of the Island ; if, therefore, it was thus anglicised in the Isle of Man, as is most likely, either it replaced a previously obscure and non-landholding MacGilbrid in the Southern parishes, or the partial translation took place when a family of MacGilbrids came South and rented farms belonging to the Abbey. The date of the first appearance of Brydson is too early for it to have been an English version of McBride, which is a comparatively recent Irish form, and, moreover, is not found in the Isle of Man. The English name Breden occurs in the Manorial Roll for Rushen and Arbory, where Brydson is common, and as it has disappeared, it may have been assimilated to Brydson. The interpolation of the short " i " sound after the " d," which comes so kindly to the Manx tongue, would easily bring this about, and it would be assisted by the native pronunciation of the saint's name Bride, viz., " Breezha." " Vreezha " was, in fact, formerly used colloquially as an equivalent for Byidson. A signature to an Act of Tynwald in 1610, Bridgen, may be a link between Breden and Brydson. The rendering of MacGilbrid by Brydson has a parallel in the rendering of MacGilvorra (" Son of Mary's Servant ") by Morrison. Though the original form Brideson has lost its " e," the sound of the " i " has evidently never varied ; in 1722 the Earl of Derby, writing to the Governor, spelt the name " Brightson " ; see Moore, Manx Worthies, page 48.