a variegated ivy, very hardy and looks great ,though you have to pull the green leaves off to keep the contrast as it tends to want go green as nature intended

Thanks Eamonn. As I have already had a an ivy there I fancy a bit if a change. Are there any other types of climbers which are robust and quite hardy?

clematis cirrhosa are evergreen and winter flowering. I'd go for a range of clems that flower at different times of the year.
also there are some evergreen honeysuckles too.

I have a Lonicera japonica halliana evergreen honeysuckle which is brilliant, Roy.

Here's a slightly different approach, in case it helps.
At my house we always have the curtains closed when it's dark, so have no view of the garden at dinner time for 5 months of the year. It's just now getting light enough to leave the curtains open at dinner time, so interest in March and especially April is important.
On that basis, something permanent but deciduous is worth considering. You can get trained apple and peach trees to grow in a pot, flat against the fence, which will give you blossom to admire in spring, then your other benefits later. They will not fruit as prolifically as in open ground and full sun but could be worth a shot.
Or climbing Hydrangea petiolaris is deciduous but recommended for a shady spot.
I would also suggest a don't-buy: anything described as semi-evergreen (although Clematis armandii would be fine) because that translates as in a bad winter all the leaves will go brown and stay on the plant looking crappy in spring; and in a good winter most of the leaves will go brown...

Teadrinker -thank you for your suggestions. If planting more than one plant to get some variation I assume they could all be planted in same pot?

Roythefoot. Thanks for your suggestion. I am thinking of maybe having a variation of plants planted together for some evergreen, flowers and blossom.

Seaburngirl- great suggestio. See my comment to roythefoot about aybe combining some plants.

if you are going to put climbers and non climbers I'd use several large pots as they will need lots of water and feed.

Have you considered lifting some of the stones or making a hole in the concrete so you can plant direct into the soil then watering will not be as critical as climbers in pots. There is an evergreen climbing Hydrangea seemannii which might fit the bill.

Thanks for your suggestions. Will let you know when all planted up.