I th
I think it has been found there but I may be wrong. The race you mentioned is
dichrorhyncus, which as you say is smaller and can look quite matt blackish , without much in the way of spangling- see this image taken at Fraser's Hill:
ML244720331 Blue Whistling-Thrush Macaulay Library. I suspect the apparently large, slightly hooked bill, deep gape and brown tones on the wing, a bit like on this bird -
ML531024321 Blue Whistling-Thrush Macaulay Library - point to Blue Whistling-Thrush. The habitat sounds OK for either.
@Steve.Jonesy What was the elevation, roughly?