I had a though that it could be a white-breasted cuckoo-shrike (Coracina pectoralis) but I'm not completely happy with that id. I also don't think it's a grey-capped sociable weaver due to the lack of grey cap.
According to my East African bird book - yes, it is in the range. I also think that African grey flycatcher is the best match for a flycatcher in the area.
