I just got a nextbase 622gw. From Halfords and they fitted it. Power by the OBD port so it has constant power when parked. So parking mode is always active.
I had the same issue, my old cam was in 12v socket and during school holidays. I didn’t drive it for a few days and the battery depleted on the cam and someone crashed into the car and drove off.
The lead also has a low voltage cut-off so if 12v battery level drops in will stop powering the cam. So far I’ve had no issues with it at all. even when the cars parked for a good few days.
EX30 SMER Ultra