Heat your oven to 180°C/Fan 160°C/Gas 4. Take the chicken out of the fridge, unwrap it and scoop out the giblets. Pop the chicken in a roasting tin. Let it come to room temperature - this will take around 30-40 mins.
While the chicken is warming up, make the glaze. Pop the stones out of the dates, then roughly chop them and scrape the dates into a small processor or blender. Finely grate the orange zest into the processor and squeeze in the juice. Peel and roughly chop the garlic. Add it to the processor.
Pick the thyme leaves off their stalks and add them to the processor. Add 1 tsp ground cumin, a pinch of mixed spice and a good pinch of salt and pepper. Pour in 1 tbsp oil and blender till smoothly combined.
No food processor or blender? No problem. Pop the stones out of the dates, then finely chop them. Finely chop the thyme leaves and crush the garlic. Mix the dates, thyme and garlic together with the orange zest, juice, the spices, oil and seasoning. This will make a chunkier mix, but it will still give your chicken a great flavour.
Spoon the date, orange and thyme glaze all over the chicken and rub it in to make sure the chicken is well coated. Loosely cover the roasting tin with foil, scrunching the sides to seal it. Roast in the oven for 1 hr 15 mins, then remove the foil and roast for a further 20 mins till the chicken is golden brown and cooked through (pierce the thickest part of a thigh with a skewer or knife. If the juices run clear and there is no trace of pink, the chicken is ready).
Transfer the chicken to a board, loosely cover with foil and rest for 20-30 mins before carving and serving.