I've got two pots, one on each side of my front door. They're a decent size but not huge. It's north facing and I've got a clematis in each one. Every year I refresh the compost, just by about 4 inches. I always think they've had it when they die down after flowering, but they come back every year and create a lovely display.
So I would say, just go for it. Sorry I don't know the varieties, they were really cheap, I think I got them from Morrissons for £2 each. If you don't try you'll never know. It's worked for me!!
Forgot to say, there's a trellis above each one, and I just tie them in as they grow.
Thankyou Sandra, I will give it a go.