Even back in the mid-90's you could get to Oz for ?399 (Britannia Air... oh, God... never again.). I have made the flight every year or two for the last 20-odd years and, really, the price has not really changed one iota in that time. The only time I have ever paid over a grand or even ?900 for economy is a booking for a December/Xmas journey, when all prices go silly unless you get your booking in early around January.