Is our Emmersion Heater not working due to RTS switch off?

Great, thank you so much - the pictures tell us a lot. I know just how difficult it is trying to take helpful photos of barely accessible meter boxes!

The offpeak timings you gave suggest that this is an Economy 7 system, actually the Merseyside and North Wales regional variant which gives 8 hours offpeak overnight. 

This is what we can deduce from the pictures:

1. The meter appears to be recording peak usage on the register labelled TOU Rate 1 and offpeak on TOU Rate 2. That’s just as it should be, so one fewer thing to worry about (they sometimes get configured the other way round on installation).
     
   Since you have storage heaters, they are what’s gobbling up electricity. I’d expect your offpeak usage to be a lot bigger than the peak usage, and that is the case: offpeak  4832, peak 1444, total 6276. It’s possible that a good deal of the 1444 peak units are attributable to your unavoidable use of the water heater’s boost feature.
     
2. You didn’t say, but the readings indicate that the storage heaters are indeed working as they should, charging up during your overnight offpeak hours.
     
3. The circuit breakers in the lower CU are all ON as they should be, so the meter is switching power to the storage heaters and the main (lower, offpeak) immersion heater element.
     
4. That means that there is a fault in the supply to that immersion heater element. It could be anywhere on the way - at the circuit breaker itself, e.g. a loose connection to it; between the CU and the immersion heater control; inside the immersion heater control; between the control and the element in the tank; or within the element itself. 
     
   Finding that fault will with any luck be fairly quick and easy for the competent electrician you’ve found, so long as he’s familiar with Economy 7 systems - do make sure of this before you call him in. If he does find a fault, you’ll probably have to negotiate with him about putting it right.
   
   The circuit to the immersion heater should only be live during offpeak hours. He can probably check it even though it’s not live, but testing any remedy should be conducted on the live circuit. Unless he comes in the middle of the night (!), he will have to find out how to energize it for testing. This is possible by using the meter’s Boost function. He would have to trawl through the meter’s settings using both the A and B buttons to find the command labelled Start Boost. Once he’s found it, he will see that he can energize the switched (offpeak) circuit for 15 minutes or more to give him time to conduct his tests.
     

If it’s any comfort, if the electrician finds no fault at all and gives you detailed written confirmation of that (on his enormous bill!), OVO will usually reimburse you for the expense if you ask nicely.  

You shouldn’t delay before bringing the electrician in. If he finds the fault and fixes it, you can cancel the OVO engineer’s planned visit and enjoy your hot water. If he doesn’t, wait for the engineer.

That may be the end of this exercise, but do come back again if you’re still not happy with the way your new meter is behaving. Best of luck!

Thanks Firedog, 

I detect a lot of sense from these points you have set out. The understanding and competent assistance of a local electrician is indeed what's required. Many thanks.

P. S. Yes, the night storage heaters are working as you deduced from our dimly lit meter readings

It may be a couple of weeks before I update on the resolution of this issue. Thanks all. 

Hey ​@Jameses 

I’m glad to see community were able to come together to try and get to the bottom of things here. Do pop back and let us know how you get on with the electrician. 😊

Well, I have a friend who is a qualified engineer who was keen to have a look at the hot tank situation. His thorough and intelligent questions were along similar lines to the deep dive entered into by the helpers on this forum. He used one of these special screwdrivers that indicate presence or absence of current. What do you know! He found absence of current before 11:30 pm but on purposely testing shortly after 11:30 pm the 'magic' screwdriver lit up in all the relevant contact points, including the thermostat. Quietly and assuredly he told me, "yes, it's the heating element that needs replacing... definitely!"

So, I'm in no rush to move ahead with the next step in restoring normal service. I have of course now cancelled the OVO smart meter check up which is obviously not needed.

At least we haven't got any lingering befuddlement about the RTS "to be or not to be" red herring.