Hi Vin,
Why are you getting a meter in? Don't you have to specifically ask to have one fitted?
Southampton has been classified as being "under severe water stress" so they are allowed to fit them compulsorily. Plus, we're going to be the first area in the country to pay extra in the summer - water will be 6% more in the summer than the winter.
Its effect on me should be trivial. I use about 30L a house, which is about 16p at our current water price (allowing for waste when creating pure). If I can avoid paying sewerage on it, it's 6p. It'll be absorbed by the customers (the price, not the water).
I'll be paying that as part of a solution that generally drops consumption by about 10%, so I'm much less likely ever to be restricted from using water. I approve entirely. I don't see why water should be paid for in any way differently from Gas or Electricity. Use more, pay more.
Vin