Whisk together the olive oil, garlic, lemon juice, oregano and seasonings. Toss this in a large bowl with all your vegetables.
Use a large pointy stick stuck in an onion for the base for your kebab and carefully thread the marinaded vegetables and halloumi onto it.
Preheat the oven to 200°C and roast the kebab for around half an hour - you want the vegetables to be cooked through and almost charred. Towards the end, brush with honey and place in the oven for a final ten mins - careful it doesn't burn.
Meanwhile, whisk all the tzatziki elements together.
Slice off bits of the kebab and serve with warm pittas and the tzatziki.