Note how much lighter the plumage tones are in sunshine, but there's no denying the extent of brown in the nape and rear crown.
I've just been sent some more shots, taken by the finder of this bird, this afternoon. Note in the flight shot below that although blurred, the outer tail feather appears wholly white and there is perhaps a small amount of white at the tip of T5. I think this strengthens the case for this bird being blythi but I really need to do a bit more reading up on the subject.
The bird apparently first appeared in the garden about a week ago, which goes to show that birds are on the move, even in the middle of winter. It's partial to the fat balls that the owner puts out which reminds me, I need to replenish my supply.........
There appears to be some moult contrast in the tail - central tail feathers presumably old and perhaps indicating this may be a first-winter bird?