Very helpful. I was wondering about Clematis terniflora, but I think/hope you're correct as that would mean it was less invasive.

Yes, Clematis armandii. C. terniflora blooms late season and is not evergreen. C. armandii is very widely grown where I live and has not shown the slightest bit of invasiveness.

Winter Jasmine has much smaller, yellow flowers, not white, so differences in the leaves are neither here nor there.

It should be fragrant!

The evergreen clematis grows yards at a time, will need an adequately large support surface already in place before it takes off. One that it can be pruned and trained to fan out over. Otherwise it is going to very soon shoot up to the top, bunch up there. Also its quite unsightly spent leaves aren't in a hurry to drop, so that if the plant is not kept well dispersed over the involved surface these can become hard to get at and remove.

@Embothrium thank you this is very helpful indeed.