Hi @
DenFen,
Do you have a smart meter?
Meters usually display the current rate ie 1 or 2, so a simple check is whatever is displayed between 9am and 9pm is the Day rate. If a meter displays both rates at the same time then only one will change during those hours, and even the lowest user should see a 1 kWh change over a 12 hour period.
To get the exact hours raise a complaint, e.onnext are billing you on two rates and they should tell you exactly when those two rates apply. They usually try to fob you off by just telling you to look at your meter, hence the need to complain. I had to go through this with nPower, I was asked what county I was in and when I said Warwickshire, she had no idea where that was, so it can often be a battle!
When you do get the exact hours just remember that they are for GMT. So my hours are 00h30 to 07h30, so as we are currently on BST my night rate ends at 08h30. Why they can't display the hours on the bill is beyond me, the cynic in me thinks that they avoid telling the customer in the hope that they'll use more electricity on the higher rate.
See
this post by @
meldrewreborn for identifying your hours yourself, but as I said above e.onnext should really tell you themselves, it's not difficult.