I have heard that BR will be operating re-vamped 744s on the LHR-TPE via BKK route from December, this should enable better FF upgrades.
I have had difficulty in upgrading to PL using FF miles, the 777s are usually full on this route at this time of the year.
This rumour has come from more than one source, however in aviation things can change quickly.
The 747s would have avod, not sure about the config, presume PL upstairs, elite at the front etc.
Not sure if existing BR aircraft, I expect so.