Meconopsis cambrica. I love them and use them a lot in my garden. They tolerate shade, have no pests that I've ever come across and require no care whatsoever. They self sow but I just remove the ones in places where I don't want them. They are biennial. Here it is with another self sower, Geranium maderense.

Ah right great thanks. I have nothing to worry about. Even though they are biennial I suppose they still grow back every year right? As the ones that grow next year are probably ones that were planted last year

Yes, they'll self sow for ever ... at least they do in my garden. I've never actually attempted to plant one. Never needed to.