I would recommend any of the chaenomeles (quince) but think you would be better to lift one slab and place the plant in the space if that is possible.

In sun or shade?

You could plant an evergreen honeysuckle. There are several varieties.

Thanks all of you. The patio has a good amount of sunshine. I don't really want to lift a slab. I will check out honeysuckles.

I wondered if you could grow a honeysuckle in a pot and came across this link which might be of assistance to you. http://homeguides.sfgate.com/grow-honeysuckle-pots-42925.html

You could use Trachelospermum jasminoides - it will eventually need a pot that's a minimum of 12-18 inches wide by 2 feet deep. Its evergreen and has fragrant white flowers in summer. It's a neater grower than honeysuckle and doesn't produce lots of dead wood with green growth over the top like honeysuckle does. It likes full sun, but in a harsh winter, some damage may occur. Info here https://www.rhs.org.uk/advice/profile?PID=302

Passiflora caerulea (passionflower) is another technically evergreen climber - will need a similar pot size eventually, but in a cold winter, it may lose its leaves and even be killed back to soil level, but as long as the pot doesn't freeze, it will regrow in spring. Both these plants require a strong trellis to twine around.

Be aware that any plant grown in a container is more vulnerable in a harsh winter - if the pot freezes solid for a few days, the roots will be killed.