Maybe Mrs. N Thompson? Though the stamen color doesn't look quite right.

https://www.dobbies.com/products/plants/climbers/clematis-mrs-n-thompson/

I was thinking maybe Barbara jackman from what I see on the web?

Looks like a good match. It can be awfully hard to tell with clems, though!

It's not Nelly and not The President. It does look like Barbara Jackman, it can be really hard to identify because colors vary so much online and in photos.

http://davesgarden.com/guides/pf/showimage/248527/

It looks like my Sunset.

Sunset is not that color, yours might have been mislabeled. Clematis 'Sunset'

Ya it's hard to tell colors from pictures. Not red like sunset. Mine is not sunset. It is a light blue purple with a dark pink red bar it fades to a lilac color as it ages. It does compliment the president nicely as it ages.