Aha - so the note closure here (around Cuthbertson Grove) refers to a set of houses that are now complete (actually, the Bing imagery just catches the end of construction), but the "Hopecroft View" ones are still under construction.
Thanks @Weiers Coetser !
@eliza2011 If you're marking notes as complete because they no longer apply any more, because the thing that the note applies to has been added, then (a) that's perfectly OK, and welcome, and (b) it helps to add some text that says that use you resolve the note.
Thanks all!