There's always one . . .
Please note this view is based on seeing many thousands of Black Kite and just a handful of views of Red Kite.
I think its a Red Kite - principally beacuse the wings (especially the hand) looks too long and narrow for Black Kite (which is usually rather more compact in its wing-shape).
According to "Flight Identification of European Raptors" both species have six primaries, so unless I'm hopelessly out of date (which I accept as a very real possibility) then this is not a diagnostic feature.
I also think that the tail is spread pretty wide in the act of turning, when the tail-fork can disappear, and that the vent looks to have too rufous a tone for Black Kite.
I also think that the had of this bird is plaer than I would expect fo most (but not all) Black Kites
Also perhaps a minor point, but based on seeing thousands of Black Kites in Hong Kong I often see the tail twisted out of alignment with the wings, but almost never the head.
Cheers
Mike