It’s free above your normal usage for that time of the day, they compare your recent activity (hence the need for a smart meter). In my case the electricty use for the whole of Thursday last week was only about £1.50 including the 69p standing charge. I’ll not get a lot back but as they say, every little helps
If you got 5 tomorrow, can you take pic of writing on the CT clamp, that came with the charger please. It should also be fairly snug around the cable with little play.
I think/know when my parents charger was installed, they installed a a large CT clamp non Ohme supplied medium clamp suitable for 25mm tails, hence why its charging at 3.7kW and no CT reading in the app!