Preheat oven to 180°C (160°C fan-forced). Place lamb shoulder in a large baking dish, brush with oil and sprinkle with dry rub and a little salt and pepper. Add 1 cup water to the base of the pan and cover tightly with foil. Cook for 2 ½ hours or until lamb is able to be easily shredded with two forks. Brush thickly with glaze and either shred or serve whole.
Place potatoes in a medium saucepan and cover with cold water, bring to the boil and simmer for 20 minutes or until tender, drain. Toss with mayonnaise, mustard and half the chives.
Toss sliced cabbage with vinegar and oil, a pinch of salt and pepper and serve lamb with slaw, potato salad topped with remaining chives and pickles.
