Addison, who now lives in Poole, Dorset, said he started the stunt when he was living in Great Missenden in Buckinghamshire.
“There was a postman there called Frank – the most efficient postman I know,” he explained.
He added: "To my disbelief he did and the post office in Great Missenden, hats off to them, would actually draw and write little messages and work these codes out which was fantastic."
"They had so much patience and I hope I haven’t annoyed them too much."
Addison even started writing pictures of where the letters needed to go.
And wrote in Morse code.
He said staff started adding smiley faces to the envelopes once they had solved the riddles.
