The 2 chaps turned out to be from Hamburg, and when they got their 2 wines (one for now one for later with dinner) they took it to mean drink two at a time. Went back for more beer (Grolsch and Heineken) Scotch (Johnnie Walker Red Label) which they drank with, ugh, 150 ml Cokes!
I showed them how to enhance the scotch flavour with a “wee dram of water” mit ein bischen wasser, but they proceeded heedless of caution.
Much later they finally were told “the bar is closed”. When I finally had my Grolsch- only my second beer officer after a fine bitters (Fullers London Special Ale) with my veggie lasagna, they wondered. I said “Mama’s told you ‘no’.”

I was actually awakened when the plane touched down at Heathrow.

We had to exit the secure area to go to a different terminal (Tram shuttle to the main hall)
British security was just as tight. Signs and displays showing forbidden items and acceptable sizes. An attendant handed out zipper bags for us to collect our liquids. I had to ditch the second wine, and I remembered to stow the toothpaste from the BA goodie bag with the rest of the Scotch.)