Hose pipe bans have occurred at least twice in the last 10 years so I can't agree under your assumption, but hosepipe bans overall are good.
15% reduction in leaks is not enough. No private profit making company should have the right to attack the environment without tracing at least 50% of leaks, Aka it took over 1 month to fix the one outside my home.
Sussex has a lot of open space, get southern water to put more reservoirs there.
Water meters, my property has a divert to next door within 6" of the wall and immediately inside please devise a metering solution, namely separate the supply on the street, and stop telling me the supply is already separate ! !