Best answer by Duppy
The rates shown in your statement is excluding VAT at 5%, the rate shown in your account app or web includes VAT. 12.75p/ kWh + 5% vat = 13.3875p,/ kWh.
You will also find that the membership fee stated on the statement is excluding VAT, everything is totalled up and then vat added to give the final figure. So no there had not been a price increase.