My muse has deserted me ...
Hi Sara. I'm guessing it's going to be shady - and dry too? What kind of look do you want and can it be seen from the house? If you can see it from the house you might want to have winter and spring interest and you can always put some bulbs in amongst other planting. White plants help in darker areas as they stand out and if you can get some golden foliage in there too it will lift it. Hardy geraniums will be fine there and there are loads of bright ones if you want a burst of colour rather than white. Ferns are useful in those conditions too and you can get some lighter, more golden ones, and also some pale aquilegias and white hydrangeas. White wood anemones for the spring and also the Japanese ones for this time of year will grow there. Foxgloves for verticals. I see you have a fuchsia there already- I had a very pale pink one many years ago and that could be a useful plant as it will lighten a shady space. The fir trees will take a lot of moisture and nourishment from the soil too so you'll need to use plants which thrive on poorer soil or be willing to put loads of manure and compost back in before planting. I'd do that anyway as the ground will be pretty starved.
Don't know if any of that's any use! 
Posts
How about Lamium white nancy and tiarella for the bank
Was just looking for a pic of white nancy to post but this one with the tiarella caught my eye and it too thrives in dry shade. There are also Astrantia and Epimediums both will grow in those conditions and don't forget Hostas too!
Yes. Have to say a bit weedy. Looks better climbing in amongst something else. You thinking up the trellis or up a tree?
Not sure if holly tall enough for Clematis montana Elizabeth. If not what about this one
http://www.taylorsclematis.co.uk/clematis-andromeda.html
OUCH!
From the pic it looks like light coming in enough to get flowers lower down and this one does about 12 ft. Much pettier than the Hagley hybrid or Nelly Moser that grow in shade. They always look a bit wishwashy to me. You planning on any shrubs there? Weigela white knight would grow. You could have a mini Sissinghurst going on 
White with a hint of....
I have Sara. It's lovely but needs a little more moisture in the soil that I have here. I might try again as I've improved some areas of garden and it might work now. Better get some seeds
In the sticks near Peterborough
Hi , under our holly tree ( and I too took a lot of lower branches off for the same reason ) I find oddly enough that hosta's grow well if there is only a little light getting in - and being surrounded by holly leaves as a mulch for most of the year it keeps the weeds down and the sluggs away. alpine aqualiga too .plus many of the other suggestions.
I keep the holly leaves as they are a good mulch even in the summer they keep the moisture around the plants and they dont dry up so quick .They wilt a little but after a water they perk up .