First, prepare your rosemary skewers. Remove the leaves from the rosemary stems, leaving a sprig at the top. Keep the leaves to one side, as you'll be using them to make the marinade for the cod. Soak the rosemary stems in some cold water for at least half an hour, to prevent them from burning on the barbecue. While the rosemary stems are soaking, prepare the marinade for the cod. Pour the olive oil into a large mixing bowl along with the rosemary leaves from Step 1, crushed garlic cloves and black pepper.
Cut the cod into 1.5-inch chunks and place into the mixing bowl, ensuring it's fully covered by the marinade. Cover and refrigerate for 30 minutes or so.
While the cod is marinating, slice the chorizo to around one-inch wide.
Halve each Romano pepper lengthways, then cut each halve widthways into slices of around 1.5-inch wide.
Using a metal skewer, create a hole in each piece of chorizo, pepper and tomato. Repeat the process with the cod once it has finished marinating.
Light the barbecue and allow the flames to die down until the coals are grey and ready to cook on. This should take around 20 minutes.
Prepare your skewers for the barbecue. Thread a piece of Romano pepper onto the skewer (with the skin facing upwards, towards the top of the skewer), followed by a piece of cod, then chorizo, followed by a tomato. Repeat the process once more to fill each rosemary stem.
Using a pair of tongs, carefully transfer the skewers to the barbecue and cook for 8-12 minutes until cooked through, turning (very gently) occasionally.
Once cooked, drizzle the fresh lemon juice over your cod and chorizo skewers, scatter with fresh parsley and serve with a zesty homemade aioli (see the recipe notes for the link to the recipe I used).