Caesar pitta

Name: Caesar pitta
Ingredients: 1 tsp lemon juice; ½ small garlic clove crushed; 1 tbsp fat-free Greek yogurt; 1 tbsp lighter mayonnaise; ¼ tsp mustard powder; 1 brown anchovy rinsed and finely chopped; ½ tbsp grated parmesan; 1 small skinless cooked chicken breast, or 80g cooked chicken, shredded; ¼ small cucumber cubed; 3 cherry tomatoes halved; 4 Little Gem lettuce leaves, shredded; 1 wholemeal pitta bread