I'm not a clematis expert but it does look like one I have which flowers in spring then again in late summer called 'Multi Blue'? sure someone'll put me right if I'm wrong :-)

Look at Clematis 'Double Multi Blue'

Lovely flowers!

I think it's Multi Blue as well :o) I have one in my garden.

I have multi blue too and looks like mine.

Its beautiful.

Thanks everybody - much appreciated