Well done Mike, not far from you, right opposite "Lilleys", (see pics). I must have passed it loads of times on my bike but never noticed it until I stopped to speak to someone this week and saw it. Hugo, I guess you noticed it when you were photographing the progress of the sand removal further along. On that subject the boating pond is now drained (and ponging a bit as well!) and there are many tons of guano-laden-sand in there, and the swans have wisely moved on. Maybe the green liquid which was poured in recently was to try and disinfect it?