Have re-read the account of transfer at LHR by PegasusAir above, and cannot believe that BA treat their F pax this way. Queueing for a bus for a terminal transfer! in F!! No way!
I usually travel in J, but few months ago flew in F on Air France A380 from Shanghai to UK via Paris. On arrival at CDG was met at the aircraft door (as were other F pax) and personally escorted to a BMW limo for transfer from one part of T2E to another, escorted from car the few steps thru F security/immigration and up into the La Premiere lounge to await my onward flight.
My escort returned when the flight was boarding, another BMW transfer direct to the aircraft, and escorted up the steps to the jetway where my passport was checked (leaving Schengen for non Schengen), no need to enter the terminal at all. Finally I was escorted onto the aircraft and introduced to the purser. It couldn’t have been better, made me feel like a really valued customer