I recenty switched from EDF 20:20 tariff to Eon Next Drive. I was put on the Next Flex for a week whilst they switched everyting over. I emailed their customer support to find out what the times were on switching from peak to off peak, and got very evasive answers.
When I was switched to the EV tariff, it said it was from midnight to seven, regardless of daylight saving.
I was suspicious, so I was up late last night watching my smart meter display. Midnight came and went, no change in cost. 00:30, no change. 01:00, still no change. 01:35, the cost changed to off peak tariff!!
Moral of this story, check your smart meter before you start your car charging, you may not be fully on off peak.