Welcome to FT, OzinUK.
The problem with Oceania is that it's only got two major airlines, and that no continental European airlines fly there. The BA FFP stinks; if you need to fly BA/QF, get a Finnair Plus card as it'll earn you 50% on most WHY fares.
Alternatively, you can get an AF codeshare on Qantas, or fly via SIN/BKK and credit the miles to bmi or Miles&More.
If you aren't totally pressed for time when travelling, check out the fares from alternative origin points in/around Europe. Flying from CAI, you could probably get First Class on Etihad for the price of BA Y+, and the fares from Greece and Italy aren't much higher.