Succulent - Sempervivum No 2

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. I'll go with that, until I find out otherwise.

 Hopeless!
Are You a Sempervivum?

It is all very well to race around my succulents-in-pots collection, confidently taking photographs. I don't understand why I can't 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.