le Chastel de la Roce, Chastel de la Roche
It had a gate near the water (or moat?). This gate closed by enchantment to all strangers, at least during Camille’s tenure, and beyond it, the folk of the castle could not be harmed. This did not, however, prevent Lancelot from killing them when he got into the castle; perhaps he entered by another way, or perhaps the ring given him by the French Damsel of the Lake negated Camille’s magic. La Roche was located twelve Scottish leagues from Arestueil (Arestel). Camille was at least half Saxon, and allied with the Saxons.
Arestueil was apparently in Scotland, but where isn’t discovered. It may be Glennie’s Areclutha, the area between the Firth of Clyde and the River Clyde, just below the west end of the Antonine Wall. Possibly, but not necessarily, La Roche is Malory’s Castle of the Hard Rock. There may also be some connection here with Malory’s Lady of the Rock, but it’s doubtful.
For an identification of Camille’s castle, King’s Knot is possibility:
[A] singular, flat-surfaced mound within a series of enclosing embankments, which would appear to be of very great antiquity, and where, “in a sport called Knights of the Round Table, the Institutions of King Arthur were commemorated”, at least, to the close of the Mediaeval Age.