Hi and welcome to FT!

I think you may find this recent thread of use https://www.flyertalk.com/forum/brit...e-jfk-lhr.html especially post 5. Essentially there is no sleeper service now, there is a good night service which gives a full meal onboard. When in club on JFk-LHR evening flights you can choose to eat in the lounge if you just want to sleep onboard, or have a full meal during the flight.