I understand that this depicts St Hilary and not Sir Galahad! St Hilary Church may well have been re-dedicated to this saint, popular in the Middle Ages. He lived before the great age of the Celtic saints and was from a noble family of Poitiers in Roman France or Gaul. He became a bishop and was busy fighting the heresy of Arianism which the Emperor favoured at the time. He taught St Martin of Tours to whom the Church of St Meriasek, Camborne is jointly dedicated.