I have New Dawn climber with Clematis Victoria. New Dawn is my avatar picture. Clematis Victoria is purple with a magenta bar. I have photos of them together I will see if I can find one for you.

https://www.growsonyou.com/photo/slideshow/213029-clematis-victoria-and-rosa-new-dawn/member/seaburngirl

is typical of what it looks from now on through to the frosts.
both get pruned hard in the spring with the rose tied in on the wires and then the clematis just finds its own way around.

Its best to choose a prune group 3 clematis,meaning those that flower a bit later on for some weeks, such as the viticella types. These all need pruning down to about 8 inches by mid February, which means you're able to prune your roses properly a week or two later, depending where you are and what the weather's doing, unless, that is, you have a rambling rose, because they need pruning in September.

If your rose is repeat flowering, then you will have some rose flowers out at the same time as the clematis, but pick a clematis that doesn't get too big, or it might smother the rose completely. There's 10 different prune group 3 types listed in the link below, but there are others to choose from

https://www.gardenersworld.com/plants/group-3-clematis-to-grow/

Thank you for this. I have viewed your photo, SBG, and the site you recommended, Bamboo. It was really informative and I now have a much clearer idea of how to achieve the effect I'm after. I left a comment under your lovely photo SBG.