If you're looking for climbers that are evergreen there are clematis and honeysuckles that woud do the job but you'd need to do a lot of soil improvement for clematis as they are hungry plants. However they won't mind the chalk content at all.
Have a look at http://www.clematis.hull.ac.uk/new-clemdetail.cfm?dbkey=3776 http://www.clematis.hull.ac.uk/new-clemdetail.cfm?dbkey=114 http://www.clematis.hull.ac.uk/new-clemdetail.cfm?dbkey=115
There are evergreen honeysuckles too. Lonicera henryi produces insignificant orange flowers but lonicera fragrantissima will give you scented white flowers from late winter to spring. However, they need plenty of moisture in the soil – but not boggy – so, asw ith the clematis, you’ll have to work in lots of garden compost and well rotted manure before planting and make sure they are well watered at plantin time and then given a mulch to retain moisture.
Give top up feeds every spring to keep them healthy and some bonemeal in autumn.
If climbers aren't the answer for you you need to ook at evergreen hedging plants but these will need regular maintenance and will take time to get to the height and density you need. Laurel is a thug and will require hand trimming to stop it getting too wide and high. Using electric shears shreds the large leaves and looks awful.
You could try yew which responds well to being clipped and maintained to size or copper beech which keeps its dried up leaves all winter and then drops them in spring when the new buds open.