CHICKEN LARB WITH LIME RADISHES

1½ tbsp fish sauce • 2 limes, juice, plus extra wedges to serve • 2 tsp light brown soft sugar • 2 tbsp groundnut oil • 3 shallots, finely sliced • 1 red chilli, deseeded and finely sliced • 2 garlic cloves, finely grated • 15g fresh root ginger, finely grated • 500g skinless chicken thigh fillets, finely chopped • 100g radishes, finely sliced • 2 little gem lettuces • ½ x 28g pack coriander, leaves roughly chopped • few sprigs mint, leaves picked and chopped • 40g roasted peanuts, roughly chopped