Transition probabilities from selected texts
The Somerton Man's code (without the extra line) is 44 characters long. So, if the text is purely random (1/26 chance of each letter appearing) then the probability of attaining this particular string of 44 is (1/26)^44 = 5.51027E-63. This is a good initial comparison.
First Order Transition Probabilities
English (1984 - George Orwell) 1.4641414719132793E-67
French (Les Orientales - Victor Hugo) 1.1571661202766258E-70
Vigenere Cipher (1984 - George Orwell, Keyword LEMON) 1.646391769425068E-70
German (Traumdeutung - Sigmund Freud) Note: does not account for Eszett (sharp s) character 3.8662593620911806E-73
English Initial Letters (1984 - George Orwell) 2.351742120702543E-57
French Initial Letters (Les Orientales - Victor Hugo) counting words like l'hopital as two words ("le" followed by "hopital"): 7.809561685705767E-61 discounting the "l'" (only consider the "hopital") 1.1841007473332175E-60
German Initial Letters (Traumdeutung - Sigmund Freud) Note: does not account for Eszett (sharp s) character. Though I don't think a word can ever start with this character 4.29592233581315E-64
Second Order Transition Probabilies
Soon