Tai Po Kau raptor
Dylan and Dave, - Thanks for the links.... I take your point, Dave, about the number of primary "fingers" and, Mr TAI I note your comments, too.
I think that the underparts on the bird in the photo look quite heavily barred on wings and tail, and the structure, to me, seems right for a larger bird.
But OHB is statistically more likely, if we have a shot showing the pair of bars near the base of the tail, that should nail the ID...
HUNG... do you have any more photos of this bird ?