In principle I would love to use an EV tariff - it should make sense. However, before you can really estimate the worth of switching to an EV tariff, you need to know how many KwH you will consume in the 4 hour period. I imagine very little apart from the car charge as it is clearly hazardous to use washer/tumble dryer/ dishwasher during those hours. If the EV used 7.4 Kw to charge that is presumably a maximum of 53 KwH per week which is about £5.00 saving. My problem is the Go tariff is 1p per KwH more expensive than my normal use and the cheapest Go gas tariff is about 25% more expensive than my current supplier.
EDF has a more sensible tariff as you consume many more units during the longer off peak periods, but their tariffs are too expensive at the base level.
I have concluded that although I had expected to change to a cheaper regime, I cannot!