I installed the eight posters just over a week ago. I walked passed the site a couple of days later and they were still all there and unmarked by spray paint. We walked passed the same spot yesterday, five days later, and lo and behold the following three posters have been removed. It's been done very carefully because there was no sign of any of the panel pins remaining or bits of torn corners so the mystery is where have they gone? And how long will the others remain?
So, those interested people who were planning a bike ride down to the canal to see them had better get there quick.