Longest flowering cleamatis please

[WellTidy]

I am looking for a clematis to rival my beautiful Arabella in terms of being so long flowering. I only bought it last year, and it has taken so well. It has had masses of flowers for weeks and should last into September.

I would like it to grow against my east facing fence, which is about 8 feet high. Purples, pinks and whites are our garden colours (no reds, oranges or yellows).