Preheat oven to 150°C. Season the beef generously with salt and pepper, then rub with half the oil. Sear in a large heavy-based saucepan over a moderate heat for 10 minutes, until well-browned. Add the onions and cider, fit the lid, then bake for 3 hours, until tender.
Fry the okra, half the garlic, garam masala, onion and capsicum in a pan over a high heat in the remaining oil for 4 minutes, until just softened. Season with salt. Mix in the coriander, half the mint and lime juice.
Mix the yoghurt, cucumber and remaining garlic. Finely chop the remaining mint and fold in. Season with salt.
Tear the beef into chunks, then cook until a hot grill, until lightly blackened. Serve with okra, yoghurt sauce and flatbread.