In a small bowl, make up your spice mix. Add half of this to the chicken with the remaining marinade ingredients. Set aside to marinade for an hour or so.
When ready, start the curry. Heat your oil over medium heat then chuck in the peppers and onions. When translucent and starting to pick up some colour, chuck in the ginger/garlic paste, the marinated chicken and its marinade (or aubergine, if using), along with the remaining spices. Fry for a minute, then add the tomatoes, Branston Pickle, salt, and a little water.
Cook for 20 minutes or so over a low flame. Serve with coriander, rice, naan and yoghurt!