I think that the problem would be that the are penalised for the leakage on their system. They calculate it (If I remember correctly) as the amount that is put in to the system - the amount registered as used via meters. A percentage of the rest is presumed leakage. As a result this would show...
I used to work for Thames and we had a lot of these cases to deal with. I have been away for 4 years now and looking on their site and other companies it appears they have changed how they deal with Customer Side Leaks. Back in my time you would often get either full or partial payment toward...