Onions again

We put onions in last year (late but cant recall which month) we got them from the garden shop so I stuck them in, they did nothing at all, all winter and we did look at taking them out as they looked rather sad and small.

Since feb they have grown huge but when should I be pulling them, I picked off the flower heads as they came up and the necks are thick (about the thickness of a big toe)

what do they look like when ready, pics would be great I am having a blonde moment 

Start pulling them BQ. As they`ve gone to seed they need to be used as they wont keep.