It varies by region @jamesb27 and tariff set by the supplier .. for example

You would need to be on a tariff that supplies energy at peak and off peak rates

This is exactly why i am asking this question,there is no straight answer for this,no wonder people get confused about it.

I have no idea what any of it means,i know i am on a variable & that`s about it.

The ‘straight’ answer is ..

If your tariff is not something like Economy 7 then the price remains the same through the day. 
You can see what your being charged on your plan page via your account

okay

Hey @jamesb27,

I can see BPLightlog has given some helpful advice here. This topic may be helpful:

Still don`t understand what if any off peak times is there for myself.

This all depends on the plan you have with OVO. You can see it online here: Plan - OVO Energy. On the app, you’ll find some details (but not times) on the page Account > View plan and rates. If you see both Peak unit rate and Off-peak unit rate, you may be lucky. 

Well it says i am on a rolling variable plan,i am none the wiser.

Rolling means the plan continues until you switch, to another plan or to another supplier. Variable means that the rates can go up or down, but you’ll always be given notice of any change. These terms are to distinguish the plan from fixed-rate tariffs, which as the name suggests have the same rates until the plan comes to an end, usually after one or two years.

If you don’t see separate Peak and Offpeak unit rates, the single Unit rate applies to all your usage. There are no cheap periods. To take advantage of a plan with different rates for peak and offpeak usage, you have to have a meter that’s capable of handing them. The chances are that you don’t have a meter like this. If you showed us a photo of your meter, we’d be able to tell you for certain.

No i don`t have a meter like that so i will just leave it there,cheers.

We can’t change meters from single rate to Economy 7 I’m afraid @jamesb27, so if you have a single rate meter we won’t be able to offer an Economy 7 plan. 

Okay need to re-think this then cheers.