Combine the yogurt, 1 tsp salt, the tandoori paste, 1 tbsp of the sunflower oil and 1 tsp of the lemon juice. Stir in the chicken thighs to coat. Cover and chill overnight, or up to 24 hrs. Combine the mayo, tamarind paste and 1 tsp coriander. Season. Combine the remaining 1 tbsp of sunflower oil and remaining 2 tsp lemon juice, season, then stir in the remaining 3 tsp coriander, the cabbage, cucumber and tomatoes.

Break the onion bhaji into chunks and cook following pack instructions. Cook the chicken on a baking tray lined with foil under a hot grill for 8 mins. Turn and cook for 8-10 mins more until charred. Warm the slices of focaccia under a hot grill until golden. Spread the tamarind mayo over the bases, then top with the slaw, chicken, bhaji pieces and remaining focaccia. Best served on the day but will keep chilled for 24 hrs. (The mayo, slaw and chicken will keep chilled for up to three days.)