As the area doesnt get much sun ,go with it and grow plants that will thrive here.I have similiar areas in my garden and you could achieve a great looking border here with the right mixture of foliage/flowering plants.
As its a small border a few groups of the same plant works better than loads of different ones,also consider watering needs if the wall causes a rain shadow.

Anyway just an idea:
Fatsia which is evergreen on the shadier side of the border (this could get large but is easily pruned)
An acer at the opposite end for balance.
Three to five small groups of the same plant (highest at the back) to fill the space, a few to think about are
Astrantia (long flowering)
Astilbe (good foliage and flowers)
Geraniums (long flowering)
Hostas (good foliage and colour)
Heuchera (foliage colour)
tellima (winter colour)
Ferns

"...only gets sun for part of the day."
Annelise, which part, and for how long? That could be important for what would do well there. For instance, many shade-loving plants--such as Japanese Maple--don't do well in afternoon sun, even if they get shade the rest of the day. On the other hand, many blooming plants--such as roses--can take a surprising amount of shade, but won't bloom if they get less than 4 hours of direct sun a day.

I would choose Hydrangea Petiolaris to climb the wall to give you a backdrop. They self support and do not damage the wall. They grow quite fast and in a few years will spread nicely.
Dgw's list is really helpful for the group ground planting, too. Then you could underplant with groups of bulbs for a show next spring.

Neutral soil is OK for most acid loving plants. It is alkali soil that causes them to yellow. Most acid loving plants are acid to neutral soil loving plants. Just want to expand what you think that you can grow.

My first thought was with such a big wall the beds need to be much bigger so as not to swamp plants and makes the plants the dominant feature. I would make the bed at least 6-8ft deep and a plant lager shrub about 4ft from the wall. Some shrubs that come to mine are:
Buddleia
Ceanthus
Forsythia
Kerria
Mahonia
PHiladelphus
Pittosporum
Potentilla
Senecio
Spirea Bridal veil, Anthony waterer or Goldmound.
Viburnums
Weigelas

Soome good ideas there everyone - Thanks!

Re: When this border gets some sun - about 2.30 onwards but just looked this afternoon and it looks part shaded across the back of it.

Well, I never - you live and learn on this site, concerning the acid soil loving plants, I never knew that about them being ok in neutral. An Acer is on my list now!

DRC1726 -I would love to make the border bigger but the garden is sort of long and narrow with some narrow straight borders on the opposite side of the garden to this one. I know it's boring but just wished I'd done the same on this side.

I actually have Roses in the adjacent border further along to the left of this one where they just about get 4 or 5 hrs of sun a day. I thought of the climbing Hydrangea - how many would I need to buy to cover the wall? Thought Ceanthus needed full sun? I Have Hostas and ferns in my other really shaded border to the right of this one. (North facing gardens are a bit of a nightmare)

The planting scheme of putting plants together was extremely helpful as that's where I get really stuck, plus how many of each to buy etc.. I have good knowledge of plants but balancing things out........Potentilla and Senico? Just off to check those two out now!

I would have thought that potentillas actually do best in full sun but the variety Red Ace is recommended for a more shady place where it keeps its colour better. The hydrangea is a great idea and you should only need one - they get very big once they have established, though you don't say how long the wall is (I'm assuming that 10' is the height?) A morello cherry (cooking cherry) would also do well on the wall and there are one or two climbing roses that would be OK too. Euonymus varieties in the Fortunii group are lovely and bright in the border all year, either silver or gold variegated, and easily trimmed to the size you want. Lots of perennial geraniums flourish in partial shade and would be nice in the front of the border. I do agree that it would probably be a big improvement to widen the border though to make it more in proportion to the height of the wall and make it possible to have taller plants at the back and low ones like the geraniums at the front. Without seeing the whole garden its difficult to visualise but I wouldn't let the shape of opposite border stop you widening this one. Remember that if you have climbers on the wall they will take up some of the width.

Yes, height of wall is 10ft that goes all the way to top of the garden. What are the names of the climbing roses that would be ok for here please?

A 'Morello Cherry' - that sounds interesting!

cant you put a nice statue here or a water feacture or pagoda to grab the eye and a couple of climbers etc ? just a thaught .

Now there's a thought!!!!!

just make it a feacture without needing many plants realy .

Goodness I wish I could remember the name of the rose - its a lovely yellow one, been around for years and somebody on here mentioned it quite recently. I think it might be Golden Showers, but there are others - ask one of the on line suppliers for advice.

Yellow Rambling Rose - Rosa banksiae lutea? May prefer full sun, and can get huge....but may work? (thornless and semi evergreen.) I had one that did ok with no sun after 2pm and looked great with one of the taller ceanothus (but I moved house.......it was top of the list for my new garden, but I've gone with a white one this time.)(The ceanothus got a bit more sun.)

That's two yellow roses then. The Golden Showers isn't a rambler though. You might get away with a blue clematis to grow with them- I did this once and it worked well but I'm sorry I have forgotten the variety - I know it was one that was pruned in Spring.