We have been back to see what the take up has been, and it seems that around a third of residents we gave them too are now displaying the stickers, which is a very good take up rate. In some flats (see the picture to the left) almost every resident has put them up on their post boxes.
We realise that they don't completely stop junk mail, but they do make a difference, particularly when used on conjunction with other ways of cutting out unwanted mail. (Incidentally, we also asked residents if they would prefer not to receive our literature through their doors. We are happy to report that no one asked not to receive our mailings!)