Finnair has some system where you can bid for upgrades which ought to give a much lower price than the £800 recently quoted for BA LHR-PVG on the AUP thread. I've never tried it (maybe there's some experience over on the Finnair board). I always go straight for business as you can often get a J fare to China for the price of BA WT+.
Just to belatedly welcome you to Flyertalk and the BA forum
05R, I know it's not your first post, but greetings anyway and I hope you will keep up the good work of sharing your experiences. Welcome on board.