Toast the coriander and cumin seeds over the heat in a dry skillet or frying pan, and grind. Mix in a bowl with the other marinade ingredients. Using disposable gloves, rub the lamb all over with the marinade. Cover and refrigerate overnight or for at least 3 hours.
<u>To grill the lamb:</u>
Before cooking, give the meat enough time to come to room temperature.
This cut of lamb has a relatively high fat content, and therefore needs slow cooking.
Season the lamb well with salt and get all your kebab ingredients lined up and ready to go.
Preheat the grill to medium-high. Clean and lightly oil the grill rack.
A clean grill is particularly important for this recipe, as the pomegranate golden syrup can make the lamb stick.
Place the lamb on the grill and seal on all sides. This should take about 2-3 minutes.
Move to a medium heat and cook for a further 12-15 minutes, or until cooked through, turning every 3 minutes or so.
Remove the lamb to a warmed tray.
Cover and leave to rest for 3-4 minutes while you organise yourself to assemble the kebabs.
<u>To assemble the Souvlaki:</u>
Toss the cabbage, spinach and red onion with the lemon juice and season to taste.
Slice the lamb thinly on the diagonal, across the grain of the meat, to give strips.
Warm the pitta breads on the barbecue for a minute on each side until they puff up and are easy to split.
Don't toast them, as they will become inflexible.
Split the bread down one side.
Divide the dressed cabbage and spinach mix between the pittas and top with the tomato and chilli, and finish with the garlic sauce and the sweet chilli sauce.