Soak 8 wooden skewers in water. Toast all the whole spices in a small pan. Tip into a mortar and grind with a pestle, then mix in with the paprika, harissa, garlic oil and cinnamon. Scrape into a bowl with the meat, season and squish together with your fingers. Mould the mix into 8 long kebabs, straight onto the skewers. Can be done up to a day ahead.
When the coals are ashen, barbecue for 10-15 mins, turning occasionally, until cooked through. The fat from the kebabs can cause flare-ups, so be careful. While the kebabs are cooking, mix all the ingredients for the dip. Scatter the kebabs and dip with coriander, and serve with extra harissa and warm gluten free flatbreads.