Cut the halloumi cheese into large cubes, about 16 from each 250g pack.
Place in a deep bowl and cover in the lemon, garlic and oregano marinade. Reserve any extra marinade to garnish the cheese once cooked.
Remove from the marinade straight onto the grill, turning as each piece starts to get a nice browned crust.
Place the cooked cheese on a plate and drizzle a little extra marinade over and then scatter with the chopped mint.