I'm sure I'm not the first to think of this, but I always thought it silly that codes should use the same number of symbols as the words themselves.
Now this might seem like an impossibility to be otherwise, but it's very simple - add a symbol/letter (whether at the start, the finish, the 2nd letter, or alternating in a pattern) into each word (you can have every 3rd miss the additional letter, or every 2, 5, 3, 1 etc)...the additional symbols/letters themselves then refer to a code that breaks each word. You are now not using one code, but a plethora of codes to form a sentence.
As for Turing not being as well known - the enigma code itself is not as well known as Churchill. Followers and support staff are rarely as well known as the leaders of major wars. It's not at all surprising.