Geometry simplified in https://www.openstreetmap.org/changeset/172067976

Looking at the edit history, it looks like the person who overcomplicated the geometry there was me. I think this was the first major road I'd to which I'd added separate sidewalks (for the unofficial Reverse London Marathon) and wouldn't do it quite like that now. Islands with staggered crossings and longer islands still need a carriageway split, but these didn't.