i am thinking of planting a beech hedge they will be 5-6 ft high to start off

Hi Fld,
Just a thought before you go any further - beech hedges are lovely, but it won't give you an awful lot of privacy for nearly half the year when the leaves are not there. If privacy has been an issue for your property, you might want to consider an evergreen or more mixed hedge?

An alternative, for more cover over winter, is hornbeam - the dry, brown leaves are retained through winter, but it's still a native hedge which provides food for the birds.

H,i have a beech hedge had to put in a secound row to improve cover still not real good but nice hedge mybe laurel would be good if you want good cover

yes, laurel would be better for cover, but not so good for wildlife (and i think it's boring, but that's only my own opinion).
Wot about holly? Berries very good for birds, and they like to nest in it too.

We have just bought on a corner plot and it has no fencing and because we have the road we cant put up a fence of more than 1 m. We have had holly before but my husband cant stand the thorns (what a woss) but on consideration i think hornbeam may be a good option unless anyone has any other ideas?