Put the orange zest, juice and 100ml water in a small pan and bring to the boil. Place the couscous in a medium bowl and pour the hot liquid over. Mix well, then cover and leave to absorb for 5 mins. Fluff up the grains with a fork, then add the walnuts, cheese, apricots, beetroot and seasoning. Mix the oil and lemon juice (or use your favourite bought vinaigrette), then toss well. Pack in two sealed containers, with the spinach sat on top (it won’t go soggy when layered up this way). When ready to eat, toss the spinach through.