He legally changed his name to Christopher Priest, and said he wasn’t aware of the existence of another writer by that name beforehand. The reference there claims he uses “Priest” or “Christopher J. Priest” as a way to distinguish the two. (I can vouch, from recollection of correspondence with him in the '90s, for the claim that he was unaware, but do not know if that’s why he tends/tended(?) heavily towards just going by “Priest.”)