A camellia should suffice as it can be grown as a tree by cutting off the lower branches. They are evergreen and come in many forms and colours.

You could grow Ceanothus Arboreus "Trewithen Blue" as a small tree, like scotsgran describes, is evergreen, lovely dark green leaves and masses of blue flowers late spring.

Ceanothus like the sun, camellia prefers shade so that is an important point.

I believe its a South facing garden..

Yes Dido it is. Gitatailor says so, I did not read it properly which is why I decided to comment a second time. Apologies to both of you.

just done some research into suggestions and sounds perfect !! off to the garden centre now :)

Thank-u ....