Roasted cauliflower with spring veg barley salad

Name: Roasted cauliflower with spring veg & barley salad
Ingredients: 1 large head of cauliflower, broken into florets; 3 tbsp olive oil; 140g quick-cook barley (or use normal barley but allow extra time to cook); 6 shallots, finely chopped; 2 garlic cloves; 200g asparagus tips; 1kg fresh broad beans or 200g/7oz podded or frozen weight; zest 1 large lemon; ½ small pack parsley, finely chopped; ½ small pack dill, chopped; 2 lemons, 1 juiced, 1 cut into wedges to serve; 100g Greek yogurt; ½ small pack dill, finely chopped, plus extra, to serve