A great project to use wooden offcuts, old hooks and some shelf brackets. I'd make the shelf with a surround so I could store more things in it and not worry about it rolling or falling off plus it hides some of the contents for a cleaner, more organised look
I seriously love this idea for the downstairs loo. You could create a screw or catch at the end you can't see in the picture so it is easy to remove from the wall and put on a toilet roll. They do artificial birds at Rockett St George.