Whatever it is, he or she is a beauty!
Looks like a female Grey bushchat to me.
A very intriguing bird John. Agree, structurally, it looks closer to Pied but there are anomalies in the plumage; the combination of rather strong supercilium, whitish throat and rufous bases to outer rectrices are at odds with that species. Might it be the product of mixed parentage?Structurally, this doesn't look like a Grey Bushchat to me. It seems small-headed, small-billed and short-tailed, closer in structure to a Stonechat. I also think that the head pattern is not as well defined as I would expect for a Grey Bushchat - supercilium too short, white throat not very well defined and without contrast between ear coverts and nape (usually subtle but often visible on female Grey in my experience).
It looks better for a female Pied Bushchat to me, although I concede that the pale supercilium and throat would be unusual for that species.
Looks perfect for Saxicola ferrea to me