Penelope is top of our list for this bump.
I really don't see how it could be Poppy, that's a bit of a leap I think. Penny is the obvious one, although i'm the opposite of you, don't see the point in putting a name on the birth cert which you don't intend using so ours (if she's a girl) will always be Penelope to us. probably penny to her friends at some stage but I won't encourage it!