I managed to hard wire mine and hid all the cables in the roof lining. The Fuse Box on the Drivers Side is a little easier to access in the new model as the little drawer just pops out and exposes the fuses. The fuses are 3 prong fuses. I can't remember which fuse I chose - but it was 5A and used a piggy back fuse (which is why you need to know it's a 3 prong fuse). This does mean that it is only active when the ignition is on.
Other people have used ODBII adapters which give a USB output, so it just gets plugged in just by your left knee. This does have permanent power - so you need to have a dash cam that shuts down after an appropriate amount of time or is good on power usage. I don't have experience of these.
Hiding the wiring in the roof lining is very very easy. The only problem that I have is placement of the camera. It's currently on the passenger side as high and as close to the middle as I can get - but with the suction cup holder etc. it's still quite low down and obstructs the passenger side view.
So you might want to look at a slimline style camera that uses a sticky pad to stick to the windscreen instead of a suction cup, to get it out of the passengers eye line.