This looks very like the one I have. If so it spreads by root and can rampage if allowed! Lovely burst of colour for a short time. I just cut the seed heads off and the foliage down when it gets too scruffy. It is not deterred. In spring I pull up any that I don't want. I was given a rooted piece many years ago and have never known the name.

Papaver rupifragum. We had it but it did not survive. Never set seed either which is odd.

I have it and it tends to throw the odd flower up through the summer, especially if you dead head them.
and yes it is Spansih poppy P Rupifragum.

Pennyfarthing, it's interesting to find out that they spread by their roots. Mine haven't done so yet but I would like a few more. They do get scruffy don't they?
Owdboggy, I left seedheads on last year and nothing has shown, but it seems they will spread by roots.
Sbg, I'll be pleased if it does throw an odd flower up but not holding my breathe.
Thankyou everyone for the benefit of your knowledge,