Herb id please

I pulled this up in the spring thinking it was a weed, only to discover it had a square root ball so it must have lived in a square pot at some point. .
I guess it was a supermarket living herb but i dont remember pulling it from its pot and planting it in the herb patch. I think it may be flat leaf parsley, the wife thinks dill or taragon (she would have bought it originally)
It has yellow trumplet-like flowers and long slender seed pods, here`s a pic..what do you think?


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Hi John,
Thanks for that, it could well be as i`ve never seen rocket gone to seed. The seedpods are in the bottom centre of the pic, they`re about 3" long with a line of flattish seeds inside.
It seems a bit strange why i`d plant a potted lettuce in the herb bed.. but maybe it wasnt me

 

Looks to me like Yellow wall rocket which does not have that erect growth from the ground grown type.

 

Its reasonably tall when its being supported. Here`s a pic of how it looks when upright (ish)

Seedpods

Inside a seedpod

 

Does it taste like rocket?