Not a BA experience, but back in my partier years my brother came for a visit to celebrate his birthday and we boarded an HP flight PHX-ABQ in F. I mentioned to the FA (who obviously had some experience with these sorts of things) that it was my bro's bday and we were out to set the record for the number of drinks in a one-hour flight. With many nods and winks and refills from the FA, we "landed" around 9am after 7 Bloody Marys. Unfortunately, that meant needing a taxi to the hotel and an adjustment to the rental car arrangement. With all the salt from the BM mix and the cheap HP vodka, we probably set some blood pressure records as well.