I was having a look around for any discount schemes for my parents and found this; its pretty useful for those eligible who are struggling with the rising cost of living. Its not really advertised much and so this could help others, especially those already paying more for having a meter.
From the Thames Water site (I believe other suppliers may have similar schemes):
"We understand that paying bills can be a worry, particularly if you are struggling with money.
WaterSure Plus is just one of the ways we can help make things easier, by reducing qualifying customers’ bills.
It is available for all our household customers who meet certain criteria, whether you have a water meter or not and regardless of who sends you the bill.
If you are eligible for Watersure Plus, you will receive a 50% reduction to your future charges from the date we receive your application. So send it to us straight away"