Onions, yes they really do push themselves apart [honest]
So, for the non believers.
I grow my onions in pinches in modules, and transplant module by module into their final position.
From here on in, I leave them to it.
One picture is of the onions as they are now [this season's] and the other is last seasons, which are ready for picking soon. You can take the largest one, and leave the smaller ones to carry on growing, if you do it carefully.