Cheers! Coming the other way, there's no question that I need to own the whole lane. Not only is it a tiny bit narrower, but there's the T-junction, and a second island.
I've tried owning the lane on and off through the first pinch point, and I've slowly come to the conclusion that it's plenty wide enough that I probably only need to do it if there's a wide or fast vehicle wanting to come through. There seems plenty of room for a normal car to pass, and to leave me enough room to feel comfortably safe. Compare the green car passing through the pinch point with the silver car passing me with oncoming traffic 500m further on. I'm almost thinking there's more reason for primary through that stretch than through the pinch point.