That was the one at Woking, a great improvement on the one at Droitwich in 2012, which required a ladder as well, and necessitated the invention of the Patent Droitwich Funnel, which can be seen in use in the photo (it's a traffic cone with the end cut off). Bearing in mind that this was a historic boat gathering, and many historic boaters prefer the more traditional type of Elsan that doesn't have an emptying spout!
Best ever elsan point was at Penton Hook, apparently there was even hot water for rinsing out!