Thanks @Paringa - for some reason the EA don't seem to have shared this information with me, despite the eight hundred quid I give them every year... I could have looked pretty stupid turning up at a water point, as I have done for the last thirty years, and finding no hose, or not being able to use the collapsible one I carry for emergencies.
There are approximately 15,000 boats registered for use on the upper Thames, if each one now has to carry its own, special, 7m hose, that creates a requirement for an additional 105km of plastic hose (mostly to be used once or twice a year). In what way does that put "environment" in "Environment Agency", I wonder?