Not a Knight Commander, a Knight Bachelor (Score 4, Informative)

Sir Pterry isn't a Knight Commander (which is a title within various British Orders), but a Knight Bachelor (which is a title outside the Order system). Formally, there are no initials he can add to his name as a Knight Bachelor, but many add Kt. So he could be styled "Sir Terry Pratchett, OBE" (Officer of the Order of the British Empire), but not "Sir Terry Pratchet, KBE" (Knight Commander...).