I pay about 700 a year, but with 4 adults (two "young adults" included who, sort of sadly, are not of the room reclusive smelly variety) in the house, I hate to think what it might be under a meter. I also have a wife that feels that if you so much as look at a towel, then it has to go back in the washing machine. This yields maybe a dozen to 15 loads of washing per week.
Then there is 1/3rd acre of garden and countless hanging baskets and other assorted shite. Oh, and a thirsty guinea pig!
So I will leave the meter switch for a while I think. I did do the gas/electric one a while ago. Saved some money but the saving was soon swallowed up by a price increase. Haven't been bothered to look since.