Whole roasted masala chicken and potatoes

INGREDIENTS

• 4 tbsp lemon juice
• 2 tbsp peeled, finely chopped root ginger
• 2 tbsp finely chopped or crushed garlic
• 3 hot green chillies
• 1 tsp salt
• 1 tsp ground coriander
• 1 tsp garam masala
• 1.75kg (3lb 14oz) whole chicken
• ½ tsp chilli powder
• ½ tsp freshly ground black pepper
• 6 tbsp olive or sunflower oil
• 5 medium potatoes
• ¾ tsp of salt
• ¾ tsp freshly ground black pepper
• 1 tsp ground cumin
• ½ tsp turmeric
• 1 tsp Kashmiri (mild) chilli powder