Huidesain, Huidesan, Huidesanc, Huidesant, Huidessan, Huiudesant, Hussidan, Huydecan, Huydecant, Windesant, Wisant, Wissant, Wydesan, Wyndesan
A port in France fortified by King Nentres of Garlot during the early Saxon invasions. When King Idres was put in the city of Nauntes, King Nentes was put into Windesan with 4.000 knights to watch by water and by land. Nentres being king of Garloth, the city of Windesan likely was in or was near his own territory, which probably was in the north, possibly East Lothian.
During Mordred's rebellion, Arthur's army waited in Wissant for the right wind to bring them back to Britain and face Mordred's forces.
For Windesan I suggest Berwick on Tweed. Glennie (who, however, identifies Berwick with Joyous Garde) describes it as
crowning ... the northern heights at the mouth of the Tweed, looking eastward on the sea, that dashes up to high caverned cliffs, and commanding westward the vale of the beautiful river, here flowing between steep braes, shadowy with trees, or bright with corn and pasture...