The thing I love most from the lamb roast left-overs in lamb rissoles.

Mince the left-over lamb (you can mince or shred finely in a food processor. Also add a finely chopped onion and grated carrot. (You could also add celery or green pepper, whatever you have on hand)
Add a good pinch of mixed herbs, some ketchup or chutney.

Mix all together and add a beaten egg.

Form into rissoles and coat with a little flour.
Flatten slightly and fry in a little oil, turning to cook both sides

Serve with mashed potatoe and other vegetables.

I also like these cold, in a sandwich.