If you want to thank the people who answered, you just go to the bottom of the thread where there is a box you can type in. Type in what you want to say and everyone who has responded gets a message that there is more to read on your topic. Easy peasy! :-)

Re the water you run off waiting for the hot to come through, you could collect this and use it for watering - just need a big bottle or jug, or a container like campers use (one of the small ones, not a big rolly keg, unless you can fill it with a bit of hose).

Washing up water is usually pretty filthy when you've finished - laden with grease and food bits, so I wouldn't use that. If all you've done is rinse a mug that would be OK to put on flowering plants.

I keep a bucket and a plastic jug in the bathroom,for the same reason as you,Sue..and get at least 3 full jugs ,every time.,before it runs warm...soon fills a bucket ! I also use my washing up water,but as Beattie suggests,not if its greasy or with gungy stuff..it goes on the roots of bigger shrubs,with no ill effects..all are fine,and I've always done it..cleanish soapy water can also be thrown on rose bushes to wash aphids off..as you will guess,I am a fanatic at saving water..and just hate to waste it..also on a water meter,so even more reason..

If you are concerned about the detergent you could change to a "green" one such as Ecover or a supermarket own brand. They are just as effective at washing dishes.

Thanks everyone. So nice to know you are out there.