i did BKK LHR in F earlier this year and it was an excellent experience except selection of movies but it has improved since...
I also flew two times another route to Europe in C during last 12 months and everything was good.
you should have chosen the night flight to LHR, where they use the very new 777-300ER; the older version for day flight
there would also not have been any problems with your meal selection and they serve dinner after departure and breakfast 2 hours before arrival and between you can get snacks anytime
on dayflights to Europe, you have also a peculiar food concept on other carriers...