Mix together all the ingredients for the dressing in a small bowl. Set aside until required.
Cook the sweet potatoes in a saucepan of lightly salted boiling water for 2 minutes. Drain well and chill until required.
When ready to serve, heat the oil in a large frying pan, add the sweet potatoes and fry for about 10 minutes, turning once, until golden.
Meanwhile, place the haloumi slices on a lightly oiled foil-lined grill rack. Cook under a preheated moderate grill for about 3 minutes until golden.
Divide the sweet potatoes, cheese and rocket between 4 serving plates and spoon over the dressing. Serve immediately.