I had a hard wire kit for my Nextbase 512GW that I had in my old car. Fitted it myself following instructions I found here somewhere.
I used a piggy-back fuse holder RM and the fuse for the rear wiper, which is switched so the dashcam would switch itself off with the ignition. From memory it’s fuse 37, but can’t remember exactly and I’m away from my home computer so can’t check the PDF manual. Earth wire was attached to the 10mm bolt at the end of the dash frame.
Overall a really easy thing to do - the biggest potential pitfall is if you decide to disconnect the wires (or pull the fuse) for the passenger airbag and thff Ed n turn the ignition on. If you do that then you’ll need a VCDS reader to reset the airbag system via the OBDII port or you’ll have a warning light on the dash (and that’s an MOT failure).
Hope that helps!