Saving water - How exactly?

I recently received a pack fromt he local water supplier which claims will help me save water. This is a good thing. Reduce, reuse, recycle, right?
I already have those toilets with the dual flush system, a short flush for when you've just had a pee and a longer flush when you've doen soemthign more solid. I can also understand how a restricter reducers the flow in the shower thus using less water.
But there were a couple of items that I just can't get to grips with. One is a sort of gel pack that goes in the toilet systern to take up space which would otherwise be filled with water, thus reducing the amount of water that is flushed. Great except that I already have modern low level systerns with almost no water in them anyway. If I stick one of these little baggies in there'll be nothing left to flush with and it'll jam the operating mechanism. I might as well just spit in the pan instead.
Next is a gizmo that goes in the end of the tap. This sort of aerates the water, which is great as it makes ordinary drinks taste fizzy, albeit for a very short while. By introducing air into the water this reduces the volume of water flowing through the tap, thus saving water. Huh? How does that workl? If I have a 2 litre kettle to fill I need 2 litres of water. Adding air to it just means it takes me longer to fill the bloody kettle. This does not save water it just means it takes longer to fill the kettl;e.
Even more frustrating is the energy saving boiler I fitted. I used to have a tank full of hot (or warm at least) water available on demand. Now I have a combi boiler which theoretically gives me hot water on demand - except you have to run the tap for about three minutes before it gets warm - or even longer now that the air has been introduced into the equation. So, by trying to save water I am wasting water - and time. If this is green something has gone wrong somewhere.
What the water company should have provided me, free of charge, is a solar water heater, so that the water going to the boiler is preheated thus eliminating the waste water, AND reducing the fossil fuel required to heat it up - a solar heater raisng it by only a few degrees would make a huge difference to the fuel bill.
So get your act together Yorkshire water.