I stumbled across something today, which might be significant or not. That wonderful site SecretFlying has an Air China deal, London Gatwick to Ho Chi Minh City return for around £360. What's strange is that when checking the itinerary on Air China's website, the economy class books into P fare. Now, Aegean's chart shows P as First Class, earning 200%

If this did post as P (and that's a big if), then according to my calculations that would be almost 29,000 miles for £360!