I've complained about the temp before (even in F) & usually been given down the run-around. Given I fly to LHR a lot I 'know' they set it high, but trying to get it corrected takes an act of Gawd. I've been given a variety of lines why it is what it is & that it hasn't changed (even when it went from cold - takeoff - to hot - sleeptime), even when I know better.

Cheers.

PS - F is where the thermostats are on 777...