Tip the rice into a large bowl and cover with cold water. Leave to soak while you make the curry.
Peel and finely chop the onion. Peel and grate the garlic and ginger. Halve the chilli and flick out the seeds and white pith. Finely chop the chilli. Roughly chop the tomatoes.
Heat a large frying pan for 1 min. Add 1 tbsp oil and the chopped onion. Season with salt and pepper. Fry for 5 mins over a medium heat, stirring, till the onion is just softened.
Add in the garlic, ginger and chilli. Cook and stir for 2 mins. Add 1 tbsp tikka masala spice mix and 1 tsp turmeric and stir together to coat. Add the chopped tomatoes, 200ml coconut milk and 200ml boiling water. Pop on a lid and simmer for 10 mins.
While the curry is cooking, drain the rice. Tip into a pan. Pour in 300ml boiling water. Add a pinch of salt. Cover. Bring to the boil. Turn the heat right down.
Simmer for 8 mins till all the water is absorbed. Take off the heat. Set aside, lid on, for 2-4 mins to finish cooking the rice.
Cut any large chunks of fish in half. Add the fish pie mix to the pan and put the lid back on. Simmer over a low heat for 5 mins.
After the fish has poached in the curry sauce for 5 mins, stir through the spinach. Put the lid back on and cook for a further 3 mins.
The rice should be tender and the fish cooked through. Taste the curry and add a little more salt and pepper if you think it needs it. Serve in warm bowls with the rice.