We had one fitted just before xmas. I Newcastle. Our bills dropped from just over £40 to £20 a month. We have no garden, hardly ever wash the car, prefer showers etc.
If you have a leak you don’t necessarily get charged provided you get it fixed within a certain time limit. Besides, if I had a leak I’d like to know before it did any real damage.
It wouldn’t figure in our decision to buy a house. In terms of what we spent overall it is a tiny figure and there were much more important considerations. We were quite picky with our house choice though and what we bought was a bit different from the very typical 1930’s semi that is seemingly on every other street in Newcastle.