Not wide enough really - you'll only be able to fit smaller shrubs in there, and they'll be like ducks in a row. Be better if you could have wider parts to get a more layered effect, so a minimum of 3 feet wide with parts 4 or 5 feet deep, if that's possible. Here's a little list of small ones: Hebes (but only ones that get less than 4 feet) such as H. 'Youngii' or 'Autumn Glory', Spiraea "Goldflame",, Cistus corbariensis, Halimocistus, Santolina, Senecio, Lavender, Convulvulus cneorum, Berberis thunbergii atropurpurea 'nana', Berberis 'Bagatelle', Caryopteris clandonensis.
If you are able to extend the width, then you can add larger shrubs such as Weigela, Forsythia, Ribes, Cotinus coggrygia Royal Purple, Berberis darwinii, Escallonia, Elaeagnus to name a few. And don't forget the perennial stuff, like Phormiums (evergreen) campanula, geraniums, etc.

hi bamboo

many thanks your advice is much appreciated

Wmc