Have a look at your meter during the day to see if you are on normal tariff or low tariff. If it shows low tariff, you may have a faulty meter. Just because you get a low tariff from 12 pm till 7 am doesn't mean that it switches at that time. When the clocks change the meter times don't. Meters change to low tariff at differnt times, if they all changed at the same time it may overload the system. Hope that made sense.
Homer.
November 2009