Place the wood pigeons into a medium bowl. Add the crushed juniper berries, the lemon zest, thyme leaves and 30ml/1¼fl oz of the hazelnut oil. Season, to taste, with freshly ground black pepper. Cover the bowl with cling film and marinate in the fridge for a minimum of four hours, preferably overnight.
Preheat the oven to 200C/400F/Gas 6.
Heat a large non-stick frying pan over a medium heat and add the butter. When the butter has melted, add the wood pigeons, skin-sides down, on one breast. Cook for two minutes, then turn the wood pigeons to cook the other breast. Transfer the wood pigeons to a roasting tin and cook in the preheated oven for four minutes.
Remove the cooked wood pigeons from the oven and set aside to rest for 4-5 minutes. When the meat has rested, cut the breasts of both birds away from the carcasses and set aside.
Return the carcasses to the same large frying pan used earlier and cook for 4-5 minutes over a medium heat, until lightly browned. Add the gin, reduced chicken stock, juice of one lemon and the brown sugar. Season, to taste, with salt and freshly ground black pepper. Cook until the volume of liquid has reduced by one-third, then strain the liquid into a bowl. Keep the gin vinaigrette warm. (Discard the carcasses.)
Meanwhile, remove the skin and cores from the pears and cut the pear flesh into matchsticks. Place the sliced pears into a small glass bowl and add the remaining lemon juice. Mix to make sure all the pear has been coated in lemon juice (this will stop the pear from turning brown). Add the rest of the hazelnut oil to the pear and season, to taste, with salt and freshly ground black pepper.
Mix together the baby red chicory leaves, baby red chard leaves, watercress, toasted hazelnuts and pear mixture in a large bowl.
Slice the wood pigeon breasts thinly and add to the leaves. Drizzle over the gin vinaigrette.