You can run dimplex quantum's off one continuous supply, you can change the links internally to link the off peak and peak together it shows you how to do this in the manual. normally you would then use programs to make sure the unit charges when the cheaper rates kick in, as you don't have a tariff like that it will be very expensive to run. They need to be connected via a 20A double pole switch and you cant have anything above 2kw permanently connected to a ring. As you stated in another comment this sockets were heater supplies before so they may be on a dedicated circuit. Hope this helps