I had wondered about that, Shooty, and thanks. However, if so, I'm wrong on 50d, the answer to which is a pseudo-name from P Eye's series. The clue to that is: "Butler's candid preface to his famous classic film quote" (5,8) Clue specifies that it's anagram of "irked rifleman," so I've got "Frank Limideer" which seems to me to be correct, hence -R- for 3 letter part of answer to 82ac.