I agree that, in the absence of night storage heaters, it is almost always going to be cheaper to have a single tariff. However, as I've pointed out before, that's not inevitable, so it's probably worthwhile looking at one's individual circumstances before deciding to get rid of a dual tariff, even if one doesn't have storage heaters.In that case, get rid of the dual rate / economy 7 completely and change to a single rate tariff.
It will be significantly cheaper ....
I am probably extremely atypical. However, as the below graph for the past year shows, with cheap-rate electric water heating and given our semi-nocturnal lifestyle which enables most high-load appliances (WM, DW, Dryer) to be used at cheap rate, we generally manage to maintain 40%-50% of our usage at cheap rate. With the financial break-even point being about 35%, the effect of this pattern of usage is that our electricity bills are 10-20% lower than they would be without the dual rate (in our case, E7) tariff. (The dips down to low cheap-rate % relate to days/periods when daytime usage was high {usually because of visitors} - which can be seen most dramatically over the recent Christmas period)
Kind Regards, John