Why is my storage water heater not working at off peak times?

Looking at your image, you have both the Normal Supply and Off peak supply switches in the “On” position. What kind of meter do you have for your electricity? If you are not sure, it would be helpful if you supplied a picture of the meter so that its associated wiring can be seen. There are a number of people here who are experts with heating and hot water in all electric properties.In the meantime, I would turn both switches off. I believe that the Normal Supply switch is only for use if you need to top up your hot water during the day for some reason when you then use the Boost buttons. I have found a link to this controller and there is also a link on the same page for a user manual. I am not sure that this will fix your problem. https://www.securemeters.com/uk/product/electric-water-heating-controls/bx2000-hot-water-boost-control/

I have a pre payment meter and I have also has to turn both switches off as it was charging me 62p per hour just now. I would have to look for a user manual. Thanks for the link!

From a quick look there your IHD is saying that at 6:20 you are using 3.28 kW, and that is costing you £0.65 per hour.

If you work it out (65 / 3.28) that’s a tariff of 19.8147 pence/kWh which seems to be an  off-peak rate, although high for current OVO E7 rates.*
TBH though I’m not sure what the current E7 rate for PAYG customers actually is (and I cant look it up at the moment because the ‘Our Plans’ page is giving an error).**

*It may simply be that your IHD does not have your correct current tariff set, it happens.
“£” values shown on a IHD are only an indication and can be inaccurate if the tariff rates on the IHD have not been updated to your current tariff.
You will be charged at the correct rate of your Plan, whatever the IHD is saying.

**If you look at your plan on the account portal, or app, or on the email/letter that you got when joining OVO, or on a statement if you have had one, then what does it say that your peak and off-peak rates are?

Hello ​@danielleomosefe 

Just to clear up a couple of points.

1. ​@Nukecad worked out your offpeak rate (at 06:20) to be 19.81p/kWh, while your plan says it should be 18.88p. The difference is just the 5% VAT which isn’t included on the Plan page. 
2. Your meter (thanks for the clear photo!) shows two things:
   1. the current reading of the offpeak register called Rate 2. The display will usually cycle through a number of screens, including TOU Rate 1 (peak) and Rates 3 and 4 (unused unless you start generating your own power using solar panels or a windmill!). 
      This doesn’t mean that the offpeak register is active, even though it is …
   2. In the bottom corner, LC indicates that the switch (called ALCS) inside the meter is active, delivering power to the grey cable marked 5 L. If the ALCS is properly configured, LC should go away at the end of the offpeak period. If you see LC during the daytime, it might indicate that the ALCS needs tweaking.
   3. The 3.28 kW reading on the IHD is quite normal when the immersion heater is on - they are usually rated at about 3kW.  The Cost per hour of £0.65 is an instantaneous figure - it just shows what the cost would be if you continued using 3.28 kW for a whole hour. Common hot-water tanks usually only take a couple of hours to heat up from cold, so a full tank of hot water shouldn’t use more than £2 of electricity a night.
   4. I’m not familiar with the immersion heater timer you have. I’ll have a look at the leaflet Nukecad helpfully unearthed, but the two switches are for two separate heating elements in the tank, the offpeak one is at the bottom and the normal one near the top. The offpeak one is only active in offpeak hours (that’s what the ALCS is supposed to do) and explains why the red light is on at 06:20. It should go off when the offpeak period ends. 
      I would expect that the Normal switch will only deliver power to the upper element when you press one of the Boost buttons. This is for emergencies - when someone’s used all the hot water and you need to wash up, say. But I might be wrong … Please come back and tell us whether the offpeak light is on anytime during daytime.