Very beautiful guest. I went to Beth Chatto's garden today and saw a clematis blooming on the ground and about 60 foot up a tree in stages in three places. This was in the woodland garden. I wonder ,did you keep the name tickets of these 2 plants? They are wonderful plants if you can get them to perform well.

That looks like clematis Piilu and it will produce 2 types of flower Kevin.
On unpruned stems they'll be double flowers (as above) and on pruned stems it'll produce single blooms, could this be what's happened ?