I've been looking into "dash cams" etc recently as I was thinking of getting one for mine. Halfords do the Nextbase range of cams and the "402g" (their top model) gets fantastic reviews online regarding set up and playback etc
As far as I know they can be "hard wired" to the car so they can be left on either during the day in the works carpark(my case) or overnight(your case).
I'm not 100% clued up on it all tbh, however I'm sure a decent quality dash cam is what your after. It might have to be specially wired if you want it to keep running overnight etc though.