Small tree ideas for screening (with pictures!)

Hi there,
We are trying to give our garden a makeover so that it's lower maintenance and a bit more interesting to look at (it's currently just patio and lawn). We don't get much time in the garden so when we do, we'd like to be sat out enjoying it rather than keeping on top of maintenance.
In terms of rough design we quite like the look of something like this - i.e. a smaller lawn with some gravel behind, some stone features perhaps and small shrubs.
Our garden is south facing and at the end there is a 6 foot high fence with overlooking houses beyond. We'd like the garden to feel a little more private and so are looking for ideas for a few small trees or plants to make it feel a little less overlooked. It'll look a bit like this...

Remember it's south facing and so with the fence, anything below 6 foot will be largely in shade. We don't want to go much higher than a total of 8 feet or so though.
The ideal candidate would be purchased mature, very slow growing and low maintenance. We are in the very south of the country so the climate is pretty good (for the UK!).
What sort of trees or plants do you guys think could be used in a situation like this? We've looked at...
European Olive tree (I'm not sure they are 100% suitable or how we'd keep them from growing too large, can they be pruned?).
Acer pseudoplatanus ‘Brilliantissimum’ (they grow slowly but reach 4 meters eventually which would be too tall. And I read that they are best left only lightly pruned apparently)
Prunus ‘Snow Goose’ Cherry Tree (would probably get too big?)
Frosted Thorn Tree (Crataegus Prunifolia Splendens)
An obvious choice for screening like this would be bamboo but I fear that would need a lot of looking after or it would run riot!
Any thoughts on those, or anything else we might not of thought of?
Any help would be gratefully received as we are a bit clueless!
Posts
How about a lilac, magnolia stellata, buddleia?
Lavatera Barnsley would screen in summer. Honeysuckle, trachleospermum and Jasmine would cover quickly but you would need trellis. Some bamboos don't run. The acer would be good, you can prune before it gets too big.
If you had some trellis, you could try a golden hop. Humulus lupulus Aureus.Very quick growing.
I know it's only going to be in leaf in summer, but that's probably when you want the screening.
How about an Amelanchier? I have one in my garden - 10 years old and only lightly pruned last year and it is only 8 ft high tops. Lovely tree - blossom and then autumn colour. Buddleia would do the trick too and fairly quick to grow,
The problem is , none of those trees provide evergreen screening,only spring through to autumn. You are in the house more in winter so will look out at the garden more, so still need privacy. I suggest Photinia as an alternative. A row of them will look good.
Cotoneaster franchetti is evergreen, attractive, nice red berries for the birdies, easy to trim with a hedge trimmer. Camellia will tolerate semi shade, evergreen, loads of flowers in spring, but slow growing, a bit gaudy to some, and really needs hand pruning, albeit every few years. Yew is slow growing, evergreen, not sure about semi shade. Euonymus is common where I live. Chaenomelese (spelt wrong, aka Japanese or flowering quince) is not evergreen, but does form a dense growth, easy to trim, lovely flowers, very attractive, birds like it, edible fruits. There are said to be bamboo that do not spread, but I can't say I know.
You can get some fast growing bamboo that doesnt run riot, or you can contain the roots, it looks pretty, sounds lovelly (yes, really) is evergreen not expensive for a large run.
Oh, The Russian Vine, with white flowers.
Not Russian vine. A neighbour has it in his front beds, and cannot get rid of it. It grows very fast, I think it is closely related to Japanese knotweed.
Pyracantha, white flowers and either red, orange or yellow berries in winter. Cotinus, eleagnus, euonymus, viburnum.