Can anyone help me to choose a plant?

Any climber you put in a pot won't do nearly as well as one in the ground. I was going to suggest Eccremocarpus scaber (on a south facing wall, its likely to remain green all winter if you live in the south) and will be in full flower by May at the latest (possibly earlier) and will remain in flower up till September October time. I guess if you use a very large pot and protect the pot during the winter, it might work.

Just realised you live in the North East, so might have to think again about that, means it'll be even more vulnerable through the roots if its in a container. They are easy to grow from seed though, so if you liked it (think there's a picture on this site, or google it, you could regrow it easily. There's always Jasmine nudiflorum. Trachleospermum jasminoides might be worth a look, though I don't know, again, how hardy it'll be in a pot.

Thank you Bamboo, for your suggestions. Hmmm. I wonder if I should consider removing a slab or two of the patio and planting in the ground. Trouble is, I suspect that underneath the patio is a concrete base (patio inherited from the previous owners and not the best one in the world). I did have two summer flowering ceanothuses in two large pots up against the wall, but although they were supposed to be evergreen, they lost leaves constantly and I was always sweeping them up. I was (almost) relieved when I lost them to vine weevil larva and had a legitimate excuse to get rid of them!

Ceanothus would definitely have been more vulnerable in pots - probably why they lost their leaves in the winter, too cold at the roots. You can get round this to some extent by putting bubble wrap inside the pot, against the pot itself, and putting the soil inside that, keeping the wrap against the walls of the pot. I do that in metal containers outside, but don't cover the bottom with it.

I've just looked at the Eccremocarpus scaber and I don't think I'm keen on it - however, I love the look of Trachleospermum jasminoides! This would really brighten up the space, which can be a bit gloomy on an evening - although this one is a south west facing wall, there are three "walls" surrounding my patio making it a bit dark sometimes. I also like the sound of this climber being perfumed. The bubble wrap idea sounds a good idea, I'd not thought of anything like that to protect the roots a bit. It's definitely worth remembering, that tip!

I have a Trach in a pot. It does indeed smell lovely, even from just a few flowers. I'm finding it quite slow growing though, which is a pity as it's on a trellis between me & nosy neighbours! I think it probably would be faster growing in the ground. Although I live near the sea in Cornwall my garden is in a frost pocket, but the Trach survived last winter with no problem. I didn't put any protection round the pot at all.

Trachleospermum is known as a slow grower compared to other climbers.