Simmer all marinade ingredients together until the mixture has reduced and become slightly syrupy (about 20-30 minutes). Allow to cool, then refrigerate until needed.
Take the lamb steaks from their vacuum-sealed pack and allow to come to room temperature (bloom). Pour glaze over lamb and stand at room temperature while you prepare the Israeli couscous and salad.
Cook Israeli couscous according to packet instructions. Season to taste. Assemble couscous, avocado, spinach leaves and cherry tomatoes on a serving tray.
Heat olive oil in a pan and cook steaks for 3-4 minutes each side for medium-rare. Leave to rest for 4 minutes. Cut lamb steaks across the grain in thick slices.
To serve lay slices of lamb on top and drizzle any remaining glaze over the entire dish to add flavour to the salad.