Had the same letter mis-delivered to my address 3 times, each time adding another NOT AT THIS ADDRESS on it, but still came back. Eventually tweeted it to Royal Mail and was told it had been delivered to me as the address on the envelope didn't exist.... RIGHT !

We get 2 deliveries of mail a day. One from the postie, and then the neighbourhood does their own delivery of mis-delivered mail to each other later in the day.

Has become a bit of a joke now.