Looks like a female Narcissus Flycatcher (thanks for help from PWMK).
Olive-tinged back, mottling on sides of the throat. See the second photo in www.orientalbirdimages.org under Passerines, Old world flycatchers, Narcissus Flycatcher.
If so, a second record this week on Po Toi for this very rare autumn flycatcher.