Our little evergreen shrub, in bonsai form

I've no idea of the name of this evergreen bush, which s actually more like a tiny tree. It is less than two feet tall, and has hardly grown at all in the many years I've had it. I think it must be a form of bonsai and I've just remembered that a former client might have given it to me about ten years ago. It may well have been from her as she used to grow bonsai plants in her garden.

It survives the coldest winters and the driest summer days. This year it seems very healthy and I'm thinking I must repot it soon into a slightly bigger pot. I think if it was in the ground it would disappear from sight and go unappreciated. Perhaps IO must do some research on caring for bonsai trees, as I know they need to be trimmed to maintain good shape.