Re: "compliance engagement"
No you didn't top it up for free between 2PM and 4PM. You were using electricity that is surplus to demand and the suppliers are getting paid for what they can supply not what they deliver. Come the winter when we need far more power than we do in a warm summer those solar panels that are over producing at the moment will be putting out about 5-10% a day of what they are currently doing and the gas powered generators will be fired up to keep up warm and give us light. That bill will be higher because as well as the cost of gas it needs to recover its capital an operating costs both for the winter when it was well used plus the summer when it was sitting idle making no money but still accumulating its fixed cost.
You might think you are getting free power but you aren't you and all of us will pay for it later.
Good news about your car, do bear in mind that as ownership of electric cars grow and there are a few million more people wanting to charge EV's at night it will cease to be a low demand time with an 8p tariff designed to encourage people to use the base load. Use it while you can: it's not going to last.