There is a clue, somewhere in the transparencies, but any sequence which any number of slides could be placed could run into millions, and so far Sir Charles’ men have failed to find such a sequence. The trouble is that breaking a code or cipher is a finite problem, but with the transparencies they don’t even know that there is a problem. Or if there is on what level of reasoning it is set. They just haven’t thought of it, and its not accepted that its not possible to do so. So in the end it might have come down to a question of time in order to break the code. So to save time they returned the box of transparencies to the camera shop, for when ZM73 came to collect them, even though it was a year after he had deposited the roll of film at the camera shop! And to help cover up the fact that the transparencies had already been signed out, an apparent clerical error was introduced. One of the camera shop’s juniors having signed over the transparencies for another number. It was apparently pure carelessness, confusing the last numbers 01 for 10. Needless to say he wasn’t there for long, if the junior had ever existed in the first place!
Whoever Mr. Carmichael was, it was certainly very good of him to have returned the transparencies upon discovering the error. But it seems that ZM73 had doubts and suspicions, about “Mr. Carmichael’s” intentions. Because as it is it would appear to ZM73 that someone had already taken too keen an interest in his transparencies!
Be seeing you