Hi Danymac and welcome to GoY. Where are you in the UK, what is your soil like and is the site exposed, windy, sunny, shady? All these answers will help us give you better advice.

Buxus microphylla reaches 3 feet, is evergreen and makes a good evergreen hedge - Lonicera nitida is another option, though that gets a bit taller. For a low deciduous hedge with purple leaves, Berberis thunbergii atropurpureum nana.