In a large bowl, place the olive oil, garlic, lemon juice, herbs and seasoning and whisk to combine. Add the meat, coat well, cover with cling film and place in fridge for a least one hour.
At the same time, place wooden skewers in a container, cover with water and leave to soak for at least an hour. This prevents them from scorching when grilling.
Preheat barbecue or grill pan on medium-high.
Drain the meat pieces from the marinade. Thread the pieces onto the skewers. Place skewers on barbecue, cook for about 2-3 minutes, then turn and cook for another 2-3 minutes, until meat is browned on the outside but still pink in the middle. Remove from heat, cover with foil and allow to rest somewhere warm.
For the cucumber yoghurt, cut the cucumber in half, scrape out the seeds with a teaspoon, and discard. Thickly grate the cucumber into a fine strainer. Press on the cucumber flesh to extract any excess liquid. Discard the liquid and place the pulp in a mixing bowl. Add remaining ingredients, mix and check seasoning.
Place skewers on a large platter and serve with a bowl of cucumber yoghurt on the side. Fry extra herbs in a little olive oil until slightly wilted (about 1 minute), sprinkle over the skewers, and serve.