Ben's best beef fajitas

Ingredients

• 75 ml lime juice
• 75 ml unsweetened pineapple juice
• 2 tbsp Worcestershire sauce
• 3 tbsp olive oil
• 1 tbsp garlic, minced
• 2 tsp ground cumin
• 2 tsp chilli powder
• 1 tsp smoked paprika
• 0.50 tsp red pepper flakes (or more to taste)
• 1 tsp salt
• 0.50 tsp black pepper
• 2 tbsp chopped coriander, heaped
• 750 g top rump or topside in two thick slices
• 2 medium white onions, sliced
• 1 large poblano (mild) type chilli, ribs and seeds removed, sliced
• 23 red, green or yellow peppers