Yes I've hard wired one to my car while back and still working. Not Nextbase so didn't order any of those kits, but just ordered the L shaped flat blade fuse holder and branched it from No.13 fuse (Outlet 15A) on the passenger side fuse box. There are two types of fuse holder, straight and L shaped. Need to be the latter otherwise the flap for the fuse box compartment will not shut.
Of course, the earth has been taken from the side of the glove box, there's a nice nut that can come off.