economy 7 water heater running continuously since key overwrite 

I have a key meter and all electric Dimplex storage heaters and an immersion water heater designed to run on Economy 7. I had an overwrite on my electric key due to another issue. In the last couple of days I have noticed that I can hear the immersion water heater heating at all times of the day. Previously I only heard it heating up during the night on the Ecomony 7 times. I have been told by OVO already that my meter does not use the RTS signal so it’s nothing to do with the signal being switched off. I also noticed a storage heater switched on during the day today for the first time this winter heating up during the afternoon.   Im a bit concerned as to why this has suddenly happened and worried that it will start using a lot of electricity. So far it doesn’t seem to have but I’ve only just noticed it.  Can someone please advise?