With the 4 screws loosened slightly you can move the headlight on every axis. Since your other one is correctly aligned I would make a spacer using some folded card or something that fits into the gap above the correctly aligned headlight then stick this in the gap above the gammy one. This will be as good a way as any as getting both aligned.
I can only imagine that the headlight has either been off in the past or the knock on the underside of the bumper that split the bracket has been quit hard and has somehow moved the headlight slightly. Either way I wouldn't worry about it. It doesn't look like the result of a heavy shunt and a bad repair. Just normal grounding which we all get in these cars at some point.