Help with clematis

Going to add that all the C. cirrhosa are slightly tender, but they should do ok in Dorset. Here they tend to flower later and ours has been totally cut to the ground by frost twice now. The flowers do tend to hang down so you do not get the full frontal blast from them like you do with other Clematis. Also rmember that evergreen plants do lose their leaves, just not all at once so you almost always have some dead material on the plant.
The evergreen New Zealand clematis like Pixie and lots of others are also not quite as hardy as northern hemisphere ones. We have now lost all of ours after the really bad frost last winter. Lovley plants though if you can keep them.