For the nectarine-mint chutney:
1) Preheat the griddle to high.
2) Brush the nectarines with oil and season with salt and pepper. Griddle, cut side down until lightly golden brown, about three minutes. Turn the nectarines over and griddle until just cooked through, about two minutes longer. Remove from the griddle and coarsely chop.
3) Heat 30ml of oil in a medium saucepan. Add the onion and cook until soft. Add the chilli, garlic, ginger and mustard seeds and cook for one minute. Add the vinegar and sugar and cook until the sugar dissolves and the mixture thickens slightly. Stir in the nectarines and cook for one minute, season with salt and pepper. Transfer to a bowl, cool, and stir in the raisins, coconut and mint. Let cool to room temperature before serving.
For the lamb skewers with pita:
1) Heat the griddle to high.
2) Combine the coriander, cumin, mustard seeds and black peppercorns in a small frying pan and cook until lightly toasted, about 1 1/2 minutes, stirring a few times; transfer to a coffee grinder and process until finely ground and place in a bowl.
3) Add the chilli powder, turmeric, garlic, ginger, 60ml of rapeseed oil and vinegar and whisk until it forms a paste. If the mixture is too dry, add a few tbsps of water to loosen it to a paste.
4) Place lamb in a large bowl, add the curry paste and toss to coat each piece of lamb. You can griddle immediately or cover and refrigerate for up to four hours to allow the flavours to intensify.
5) Skewer 2 pieces of lamb onto 2 skewers so that the meat lays flat on the griddle. Season both sides of the lamb with salt and griddle until golden brown and slightly charred on both sides and cooked to medium-rare doneness, 2 to 3 minutes per side.
6) Drizzle with olive oil and serve with pita bread and chutney.