Mine used to run from 11.30pm to 6.30am in winter and 12.30am to 7.30am in summer (i.e. the econony 7 setting didn't change with the clocks, though that could just have been a pecularity with my meter or Southern Electric, which was my supplier).
It depends on which supplier you use, most are the times posted above but we went to manweb who will supply it for a few hours in the afternoon aswell to keep your house warmer during the day.