Perth.... there's your problem.
There are no secrets with lamb, the classic leg given a rub with EVOO and good dose of sea salt and fresh ground black pepper, then studded with garlic slivers and rosemary leaves cooked to medium is common knowledge and probably the best of the lot.
I did a leg the other night smoked with peach and plum, cooked on a weber with a slow start and finishing at almost 400F over about 3 hrs and that was a treat too.
Well, It's not much of a secret here in Oz, but it's generally not done that way in the States as far as I know.... I could be wrong. :|