Succulent - Sempervivum

Here I go being vague again! I've found a photograph of this succulent in a garden book which tells me it's a sempervivum. The experts at Blueleaf Plants agree with me.

Are You a Sempervivum?

It is all very well to race around my succulents-in-pots collection, confidently taking photographs. But I've never been confident to name any of them. Many have come here as pieces from my friend's seaside garden. She can grow all sorts of succulents outside, as she rarely gets any winter frost. She will have told me what each piece was called, but typically I haven't written their names down.