Healthy BBQ chicken

Name: Healthy BBQ chicken
Ingredients: 4 skinless chicken breast fillets (about 760g); 125g passata; 1 medjool date stoned; 2 garlic cloves; 1 tbsp balsamic vinegar; 1tsp smoked paprika; ½tsp mustard powder; 1 tsp olive oil plus extra if frying; 4 jacket potatoes to serve (optional); 2 avocados peeled, stoned and cut into large wedges; ½ lemon juiced; 4-6 tomatoes (depending on size), chopped; 1 large yellow pepper deseeded and finely chopped; 1 red onion finely chopped (160g); 20g coriander chopped