Preheat the oven and a roasting tray to 220ºC/425ºF/gas 7.
Prepare your seasoning by mixing Noubess Poultry Seasoning, Paprika, and Salt; halve the lemon and slice the onion.
Slash each thigh about 3 or 4 times to allow the seasoning and heat to penetrate directly.
Rub inside the chicken cavity with sea salt, then carefully grab the skin at the tip of the chicken breasts, making sure that it doesn't rip, and pull up gently. With your other hand gently separate the skin from the meat of the breast – it's normally connected by a little bit of tissuey-type stuff, and you can either leave this attached in the middle and make two little tunnels either side or you can try to cut away the middle.
Sprinkle a little salt down the gaps that you have made, push in the seasoning and drizzle in a little oil.
Push the lemon halves into the cavity along with the onion, then pull the skin of the chicken breast forward so that none of the flesh is exposed, tuck the little winglets under, and tie up as firmly as possible.
Rub a little oil all over the chicken skin, sprinkle over the remaining seasoning very generously all over the poultry.
Place a baking dish in the oven and warm for 5 minutes. Remove the hot tray or baking dish from the oven and drizzle with a little oil. Put the chicken into the tray, breast-side down and leaning to one side, then place in the oven. Roast for 5 minutes, then lean it to the other side, still breast-side down. Cook for another 5 minutes, then place the chicken on its bottom and cook for 1 further hour, or until golden and cooked through – the skin should be really crispy and the seasoning will flavor the meat.