It also depends how much electricity is used charging the car versus how much is used running the house. In our case, our house uses ~4,000 kWh/year of paid-for electricity and the car uses about 1,600 kWh/year in total. Not all the car charging is at home, and not all of it when charging at home is paid-for, often in summer I can charge from self-generated electricity. At a guess, the car uses only about 1,000 kWh of paid-for electricity at home, and that's all during the off-peak E7 period, usually.
Our house doesn't need much heating, but even so our electric heating uses about 2,000 kWh/year of paid-for electricity. The other ~2,000 kWh of usage is hot water, cooking, ventilation, running the borehole water pump and treatment plant air pump, etc. This means that the house uses around four times more paid-for electricity than the car.
Ignoring car charging, E7 makes more sense for us, as we need the longer off-peak rate for heating, anyway. Being able to put up to about 50 kWh into the car overnight, on the E7 rate, if needed, is a bonus, and means that I can usually have the car sat fully charged (well, at 90%) most mornings. The latter point is key, and one reason I went for the M3 LR. With aged relatives living some distance away, I never know when I may have to make an urgent trip of a couple of hundred miles or so. I'd not want to have the car only half charged in the morning, so really need as long an overnight charging period as I can get.