To make the rub put all the ingredients into a bowl and mix together. Season to taste with salt and pepper.
Rinse the lamb under cold running water and pat dry with a paper towel. Cut the lamb into 3cm cubes and put into a mixing bowl. Sprinkle the mint and lemon thyme rub over the lamb and toss to coat evenly. Season with black pepper, cover and refrigerate for 8-24 hours.
Slice the lemon in half, then cut each half in half again.
Remove the lamb from the fridge and, while still cold, thread onto the prepared skewers along with the bay leaves and lemon slices. Cover the skewers and allow to come to room temperature.
On a medium-high barbecue/grill, cook the lamb skewers for 5 minutes, then reduce the heat to medium and turn them over. Cook for a further 6-8 minutes, turning frequently to make sure all the sides are brown and crispy. Serve and enjoy!