Falco subniger

The one flying looks more like a Black but the one perched is a dark Brown.

Thanks have removed the perched pics and will list separately

Are we sure they are 2 different individuals?
Same location, time and both have tatty worn tail feathers.

yes they were different birds

There is no barring in the tail or wings and no moustache in this Black Falcon sighting 4230187.
In the Brown Falcon sighting 4230188 it has a moustache and there is barring in the tail.
Hope this helps.

To help clarify the situation of us seeing 3 different raptors within a short space of time, this is how it happened.
Driving to Namadgi not far past the Lanyon Homestead driveway Rod saw a bird in a tree near the road on the left side, when stopped I (Deb) took a few pics out of the window so as not to scare it away, I usually have my camera on me just in case. I then got out of the car as we were on the road so Rod could park off the road. I got a few more pics then of what we now know as a Brown Falcon then it flew off but surprisingly flew straight back into the tree unfortunately not in as good a position for photos. Have added another 2 photos to the Brown Falcon sighting 4230188 that show the barred tail and where it landed when it flew back in the tree. I thanked the bird for posing nicely and got back in the car.
A short drive later I spotted some white birds in a tree far off on the right, we stopped again, they turned out to be 2 Sulphur Crested Cockatoos and 2 Little Corellas.
As we were about to get back in the car Rod spotted another bird above us, we both had our cameras so immediately started taking pics. We thought it was perhaps the same bird as earlier, however thanks to “natureguy” pointing it out they are different birds. The Brown Falcon perched has a definite barred tail. Looking at our photos of the flying bird we got it matches the Black Falcon pics that come up on “ebird” as the examples also on page 94-96 of “Australian Birds of Prey in Flight” for Black Falcon, no barred tail at all. Have added another couple of photos of the Black Falcon we took, one not so good but has co-ordinates from my camera. It then flew over us, then away from us toward the direction of Namadgi.
As this bird was flying away, we spotted a pair of Wedge-tailed Eagles so more photos were taken. We could not believe the start to our day it really was amazing. Hope this helps to put things in perspective.

The colouration suits Black Falcon. A dark morph Brown Falcon would have much lighter barring on the wing tips. The "trousers" also seem longer than for a Brown Falcon. I managed a photo of a dark morph Brown Falcon (which I first thought was a Black Falcon when driving past). It shows the lighter barring in flight. See sighting: Falco berigora (Brown Falcon) on 26 Jul 2019

I have confirmed it as Black Falcon as many valid and convincing opinions have been made and it is now clear that the bird is a Black Falcon. It has also been confirmed as Black Falcon on ebird.

Thank you Illilanga and natureguy, we appreciate your efforts.