Flights London To Melbourne Generally Speaking, Is It Cheaper To Catch A Flight To London, From Sydney Or Melbourne. (on Average)?

Generally speaking, is it cheaper to catch a flight to london, from Sydney or Melbourne. (on average)? - flights london to melbourne

I come from Melbourne and I asked myself, this book is worth the flight between Sydney and FlyBuy use my points for a free flight to Sydney. Is this a good use of my FlyBuy? I'm saving euro? Or should I take the flight to Melbourne?