Channing, Tannings, Tanningues, Thaninges, Thaningues, Thanningues, Tingues, Tranurgor
Since Sagramore set out from Camelot Forest and encountered Duke Brandelis after several other pavilions and adventures, I would guess Taningues to be on the southern part of the island, possibly one of the promontories on the coast of Southampton or Sussex. I propose the peninsula at the southwest end of Sussex between Chichester and Arundel. Since Arundel is Malory's Magouns Castle, the Taningues border would be south of it.
Additionally, a squire, Helain de Taningues, held a castle in the neighborhood of Taningues. If Taningues is identified as the peninsula at the western end of Sussex, then the castle might be Chichester (Roman name Noviomagu).
Alier of Tanningues | The Legend of King Arthur
Helain de Taningues | The Legend of King Arthur