Greetings All! Can Anyone help with the following regarding Above? 1) What is the correct inner to fit an M56, And can anyone tell me its reference number / ID code? 2) Am I correct in assuming that I would need to remove it in order to find its ID? If so, does the inner simply pull off from the mounts (or is a tool required) AND will it simply push back on? 3) I am aware that there is a code letter for each year of manufacture of an inner AND I have a list from 1970 - 1990 BUT can anyone provide the letter codes From 1969 Backwards? Many Thanks!