In a small bowl combine the mint, apricots, dates, pine nuts, citrus zest and olive oil. Season well.
Push this stuffing into the centre cavity of the leg.
Tie a length of kitchen twine around the leg to hold the stuffing in place. Spread the harissa paste over the leg then pat on the cumin seeds.
Put the leg in a roasting tin and roast for 40 minutes per kilo, 20 mins per pound or until the lamb is cooked to your liking.
Remove the lamb from the oven, then place it on a chopping board to rest.
Put the roasting tin on the stove top, over a high heat. Stir in a spoon of harissa paste, if desired, plus a splash of red wine and enough water to produce gravy.
Leave the gravy bubbling until it has thickened and reduced by half.
Carve the lamb and serve with the gravy, bulgar wheat / couscous and salad.